No description available.

Thesis (Msc (Animal Sciences))--University of Stellenbosch, 2006. / This research had a dual purpose, firstly to study five muscles (M. biceps femoris, M. longissimus et lumborum, M. rectus femoris, M. semitendinosus and M. supraspinatus) of the blesbok (Damaliscus dorcas phillipsi) and springbok (Antidorcas marsupialis) in terms of the physical and chemical meat quality characteristics, and secondly, to investigate the effects of inorganic salt enhancement on the physical, chemical and sensory meat quality characteristics. The muscles differed significantly for the investigated characteristics, with the exception of a* value, chroma, and ash percentage, which did not differ in either blesbok or springbok. Furthermore, no muscle differences were found in fat percentage in blesbok or protein percentage in springbok meat. Muscle differences were found in the stearic acid (C18:0) composition, the percentage saturated fatty acids (SF) and the polyunsaturated: saturated fatty acid ratio (P:S) of the blesbok. Only linoleic acid (C18:2) as a percentage of the total fatty acids differed significantly amongst the springbok muscles. The shear force values were found to be significantly lower in the enhanced samples (blesbok: 25.16 vs. 43.75 N/1.27cm; and springbok: 23.96 vs. 34.89 N/1.27cm), which means that the enhanced muscles were more tender. The enhanced muscles of both species were found to have lower values for all investigated colour characteristics. Moisture values were found to be higher in all the enhanced muscles (blesbok: 76.53% vs. 74.38%; and springbok: 75.34% vs. 73.37%). The lower fat and protein contents of the enhanced muscles can possibly be ascribed to a diluent effect caused by the water added as part of the inorganic salt injection (blesbok: fat, 1.86% vs. 2.22%, protein, 19.61% vs. 21.67%; and springbok: fat, 1.84% vs. 2.14%, protein, 21.23% vs. 23.26%). Major changes in the mineral contents were expected between the two treatments and in both species the enhanced muscles had higher phosphorus, potassium, sodium and copper values, but lower magnesium, iron and zinc levels than the untreated muscles. Analytical sensory analyses were performed on the M. biceps femoris and M. longissimus et lumborum samples of both species. Tenderness and juiciness were significantly higher in the enhanced muscles. Although salty taste was significantly higher in the enhanced muscles due to the addition of the inorganic salt solution, it remained acceptable. Analytical and consumer sensory analyses were performed on blesbok and springbok M. longissimus et lumborum samples prepared in a stock mixture. The outcome of the analytical sensory analysis was similar to the analytical results reported above. The consumer sensory analysis showed that consumers preferred the enhanced blesbok and springbok muscles, with a significant improvement in consumers’ likeness of enhanced vs. untreated meat. This study provides important insights into the muscle differences of two of the most common game species currently utilised in South African meat production. It confirms that both species can be marketed as a low fat organic red meat source well capable of filling the modern consumer’s nutritional and health needs. It also shows that enhancing game meat with an inorganic salt solution might be a very useful processing tool to use to further game meat acceptability in terms of tenderness and juiciness as game meat is often experienced as being dry and less tender because of its lower fat content and the use of incorrect preparation techniques.

Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: The production and especially the export of game meat from Southern African are steadily increasing and with this growth, it is inevitable that more emphasis is being placed on the quality of game meat. Research regarding the effect of different cropping methods on ante-mortem stress, and as a result, on meat quality in wild ungulates, is lacking and thus the purpose of this study was to investigate the effect of some of the commonly used cropping methods on the meat quality of red hartebeest, impala, gemsbok and kudu. Antemortem stress was measured using serum cortisol levels (nmol/L), a subjective stress score allocated to each animal as well as the rate and extent of pH decline in the M. longissimus dorsi. Special emphasis was also placed on the meat quality parameters drip loss, cooking loss, colour and Warner-Bratzler shear force (kg/1.27 cm diameter). The effect of day and night cropping on the meat quality of red hartebeest, gemsbok and kudu was investigated. An exponential decay model, y = a + b-ct, was fitted to the pH data of the gemsbok and red hartebeest, and pHu measurements taken at 24 hours post-mortem. Only pHu readings taken at 48 hours post-mortem were analysed in the kudu. Day-cropped kudu had a lower mean pHu (5.40 ± 0.030) than nightcropped kudu (5.48 ± 0.041). No differences in pHu were found for the red hartebeest although night-cropped gemsbok had a higher mean pHu (5.54 ± 0.013) than day-cropped gemsbok (5.49 ± 0.014). None of the constants of the exponential decay model differed for the red hartebeest although day-cropped gemsbok produced a lower constant than night-cropped gemsbok. Mean stress scores and cortisol levels were found to be higher in day-cropped animals for both the gemsbok and kudu while only cortisol levels were higher in die day-cropped red hartebeest. Stress score and cortisol levels were found to be correlated in all three species (red hartebeest: r = 0.51; gemsbok: r = 0.786; kudu: r = 0.823). No treatment differences in drip loss or cooking loss were found for either the red hartebeest or gemsbok, while day-cropped kudu had a higher mean drip loss % (2.76 ± 0.261%) than night-cropped kudu (1.36 ± 0.361%). Night-cropped gemsbok and kudu produced higher mean shear force values (gemsbok = 4.19 ± 0.138; kudu = 4.06 ± 0.237 kg/1.27 cm diameter) than day-cropped animals (gemsbok = 3.57 ± 0.154; kudu = 3.45 ± 0.171 kg/1.27 cm diameter). Colour differences indicated that day-cropped gemsbok and kudu produced lighter meat than night-cropped animals. The results indicate no difference in the effects of day and night cropping in red hartebeest although day-cropped gemsbok and kudu experienced more ante-mortem stress than their night-cropped counterparts. The effect of conventional hunting during the day and night cropping on impala meat was also investigated. No differences were found in pH45 or pHu (taken at 45 minutes and 24 hours post-mortem respectively) although the exponential decay model, y = a + b-ct, fitted to the pH data revealed differences in all the constants (day: a = 5.424 ± 0.039, b = 1.405 ± 0.034, c = -0.385 ± 0.022; night: a = 5.295 ± 0.033, b = 1.556 ± 0.029, c = -0.184 ± 0.019). No differences were found for drip loss, cooking loss or shear force although day-cropped animals produced higher a* and chroma values. The results indicate that, although conventional hunting caused a faster and more severe post-mortem pH decline, both treatments produced meat of similar quality. / AFRIKAANSE OPSOMMING: Die produksie en veral die uitvoer van wildsvleis vanuit Suidelike Afrika is gedurig aan die toeneem en met hierdie groei is dit onvermydelik dat meer klem op die gehalte van wildsvleis gelê word. Daar is ’n tekort aan navorsing oor die uitwerking van verskillende oesmetodes op ante mortem stres en gevolglik ook vleisgehalte van verskillende wildspesies en dus was die doel van dié studie om die uitwerking van sommige van die gewildste oesmetodes op die vleisgehalte van rooihartebees, gemsbok, koedoe en rooibok te ondersoek. Ante mortem stres is gemeet deur die gebruik van serum-kortisolvlakke (nmol/L), ʼn subjektiewe strestelling wat aan elke dier gegee is asook die tempo en vlak van pH-daling in die M. longissimus dorsi. Spesiale klem is gelê op die vleisgehalteparameters drupverlies, kookverlies, kleur en Warner-Bratzlerskeurwaarde (kg/1.27 cm deursnee). Die uitwerking van dag- en nag-oes op die vleisgehalte van rooihartebees, gemsbok en koedoe is ondersoek. ’n Eksponensiële vervalkurwe, y = a + b-ct, is aan die pH-data van die gemsbokke en rooihartebeeste gepas en pHu-metings is op 24 uur ná dood geneem. Net pHu-lesings op 48 uur ná dood in die koedoe is geanaliseer. Koedoes wat in die dag geoes is, het ’n laer pHu (5.40 ± 0.030) gehad as koedoes wat in die nag geoes is (5.48 ± 0.041). Daar was geen verskille in pHu vir die rooihartebeeste nie, alhoewel die gemsbokke wat in die nag geoes is, ’n hoër pHu (5.54 ± 0.013) gehad het as gemsbokke wat in die dag geoes is (5.49 ± 0.014) . Geeneen van die konstantes van die eksponensiële vervalkurwe het verskil in die geval van rooihartebeeste nie terwyl gemsbokke wat in die dag geoes is ʼn hoër konstante a en ʼn laer konstante c getoon het as gemsbokke wat in die nag geoes is. Gemiddelde strestellings en kortisolvlakke was hoër in die geval van gemsbokke en koedoes wat in die dag geoes is terwyl net die kortisolvlakke hoër was in die rooihartebeeste wat in die dag geoes is. Daar is ook bevind dat die strestelling en kortisolvlakke gekorreleer was in al drie spesies (hartebees: r = 0.51; gemsbok: r = 0.786; koedoe: r = 0.823). Geen verskille in drupverlies of kookverlies is aangetref vir die rooihartebeeste of gemsbokke nie, alhoewel koedoes wat in die dag geoes is ʼn hoër gemiddelde drupverlies % (2.76 ± 0.261%) getoon het in vergelyking met koedoes wat in die nag geoes is (1.36 ± 0.361%). Gemsbokke en koedoes wat in die nag geoes is, het ’n hoër gemiddelde skeurwaarde gehad (gemsbokke = 4.19 ± 0.138; koedoes = 4.06 ± 0.237 kg/1.27 cm deursnee) as diere wat in die dag geoes is (gemsbokke = 3.57 ± 0.154; koedoes = 3.45 ± 0.171 kg/1.27 cm deursnee). Kleurverskille het aangedui dat gemsbokke en koedoes wat in die dag geoes is, ligter gekleurde vleis geproduseer het as diere wat in die nag geoes is. Die resultate dui aan dat daar by rooihartebeeste geen verskil is tussen die uitwerking van dag-oes en nag-oes nie, maar dat die dag-oes van gemsbokke en koedoes meer voordoodse stres veroorsaak het as nag-oes. Die uitwerking van konvensionele jag gedurende die dag- en nag-oes op die vleisgehalte van rooibokke is ook ondersoek. Geen verskille is aangetref in pH45 of pHu (geneem op 45 minute en 24 uur ná dood onderskeidelik) nie, alhoewel die eksponensiële vervalkurwe, y = a + b-ct, wat gepas is aan die pH-data verskille getoon het in al die konstantes (dag: a = 5.424 ± 0.039, b = 1.405 ± 0.034, c = -0.385 ± 0.022; nag: a = 5.295 ± 0.033, b = 1.556 ± 0.029, c = -0.184 ± 0.019). Geen verskille is aangetref ten opsigte van drupverlies, kookverlies of skeurkrag nie. Diere volgens die konvensionele maniere geoes het wel hoër a*-en chroma-waardes getoon. Die resultate dui daarop dat, alhoewel konvensionele jag ʼn vinniger en meer ekstreme pH-daling veroorsaak het, albei behandelinge tot dieselfde vleisgehalte gelei het.

Thesis (MScAgric) -- University of Stellenbosch, 2000. / ENGLISH ABSTRACT: Lipids remain one of the most important nutrients required by broilers. The growing awareness that some Western societies have too high a dietary ratio of n-6/n-3 polyunsaturated fatty acids is of direct relevance to broiler nutrition and lipid metabolism. Meaningful quantities of n-3 polyunsaturates have been incorporated into major poultry tissues, so that the production of broiler meat with high n-3 polyunsaturates becomes advantageous for the broiler industry as they are perceived as having a 'healthier' lipid profile. Unfortunately, such broiler meat is rather susceptible to oxidative deterioration, and oxidation often determines shelf life of poultry meat products. The addition of a-tocopherol (vitamin E) to broiler diets is an effective means of improving the oxidative stability of broiler meat. Elevated a-tocopherol levels in broiler feeds increase tissue concentrations thereof resulting in improved stability of membranal structures which may be expected to increase the oxidative stability of broiler meat and meat products. Three investigations were done at Mariendahl Poultry Research Station in Stellenbosch. The broilers were kept in 1 x 0.4 x 0.5 m cages in a broiler rearing house. All the trials started with day-old chicks, except experiment 1 where 3-week old broilers were used. At the end of trials 2 and 3 the 6-week old broilers were slaughtered and the carcasses prepared for chemical analysis. Experiment 1: Metabolisabie energy of Canola acid oil and Famarol acid oil for broiler chickens. In trials with 21-day-old male broilers the true metabolisabie energy value, corrected for nitrogen retention (TMEn) was determined by the balance method for Canala acid oil (CAO) and Famarol acid oil (FAO). The trials were duplicated, each time using different samples of the two oils from the same source (experiment 1 and 2). Each of the two oils were blended in two ratios with a basal diet to form the test diets, viz. 100% Basal; 96% Basal: 4% Oil; 92% Basal: 8% Oil. In experiment 3, 50 % bran was added to the maize to form the basal diet. The balance trials lasted for 3 days after an adaptation period of 4 days. The TMEn values determined by regression for the broilers of CAO did not differ significantly (P>0.05) between experiments 1 and 2. However, the value for experiment 3 was significantly (P<0.05) higher than those for experiments 1 and 2. The TMEn values of FAO also did not differ significantly (P>0.05) between experiments 1 and 2, although the value for experiment 3 was significantly higher than that of experiment 1. The addition of 50 % bran to the basal diet in experiment 3 could have stimulated the digestive breakdown process and hence increase the secretion of digestive enzymes. This could lead to an increase in the utilisation of the test lipid and therefore an increase in the TMEn value. The TMEn values of CAO differed significantly (P<0.05) from those of FAO for all three the experiments (exp. 1:30.6 ± 0.399 MJ/kg for CAO vs. 25.9 ± 0.441 MJ/kg for FAO; expo 2: 31.0 ± 0.633 MJ/kg for CAO vs. 26.1 ± 0.668 MJ/kg for FAO: expo 3: 32.1 ± 0.867 MJ/kg for CAO vs. 27.1 MJ/kg for FAO).Experiment 2: of broilers. The dietary effects of various combinations of Canala acid oil (CAO, a high level of C18:3n-3 and MUFA) and Famarol Effects of various dietary n-6/n-3 fatty acid ratios on the perfonnance and body composition acid oil (FAO, a high level of 18:2n-6 and SFA) on tissue fatty acid composition were studied in broiler carcasses and abdominal fat pads. From day-old to six weeks, chicks were fed one of six diets containing 100% FAO, 80% FAO-20% CAO, 60% FAO-40% CAO, 40% FAO-60% CAO, 20% FAO-80% CAO, 100% CAO. There were no statistical differences (P>0.05) in average daily gain (1.71 ± 0.059 g) or feed conversion ratios (1.97 ± 0.051) among dietary groups. No statistical differences (P>0.05) were found in the chemical proximate composition of the carcasses for the moisture (66.20 ± 0.112 %), protein (17.63 ± 0.484 %), lipid (15.92 ± 1.507 %) and ash (0.95 ± 0.115 %) content among dietary groups. No statistical differences (P>0.05) were found in the chemical proximate composition of the abdominal fat pads for the moisture (28.77 ± 0.112 %), protein (3.03 ± 0.484 %), lipid (63.32 ± 9.789 %) and ash (0.45 ± 0.135 %) content among dietary groups. With the increase in dietary CAO levels, the percentages of C18:2n-6 and C20:4n-6 in the carcasses decreased respectively with 1.78 % from 20.88 % and 0.35 % from 1.05 %, whilst C18:3n-3 and longer chain n-3 fatty acids such as C20:5n-3 and C22:6n-3 increased respectively with 2.25 % from 1 %, 0.1 % from 0.1 % and 0.67 % from 0.2 %. The same tendency was seen in the abdominal fat pads where C18:2n-6 and C20:4n-6 decreased respectively with 1.55 % from 20.75 % and 0.98 % from 1.2 % with an increase in dietary CAO, whilst C18:3n-3, C20:5n-3 and C22:6n-3 increased respectively with 2.13 % from 1.15 %, 0.45 % from 0.03 % and 0.95 % from 0.05 %. The n-3/n-6 ratio in the carcasses and abdominal fat pads increased respectively with 0.16 % from 0.06 % and 0.19 % from 0.06 % with an increase in dietary CAO. These results clearly indicate that dietary CAO enriched with a-linolenic acid lower saturated fatty acids respectively in broiler carcasses and abdominal fat pads with 4.88 % from 31.6 % and 10.63% from 31.1 %, whilst increasing monounsaturated fatty acids with 3.87 % from 44.95 % and 7.25 % from 46.7 % respectively and polyunsaturated fatty acids with 1.02 % from 23.45 % and 2.38 % from 23.2 % respectively. Experiment 3: Effect of dietary vitamin E on the performance of broilers and oxidative stability, colour, microbiological stability, fatty acid composition and pH of broiler meat during refrigerated and frozen storage. Experiment 1 was carried out with 220 one-day-old broiler chicks to evaluate the effect of eleven concentrations of vitamin E (0, 20, 40, 60, 80, 100, 120, 140, 160, 180 and 200 mg a-tocopheryl acetate 1 kg diet) on their production performance and the oxidative stability of their frozen broiler carcasses. The diets with vitamin E levels 0 to 100 mg were fed from day-old to 42 days of age while the diets with vitamin E levels 120 to 200 mg were fed from 21 to 42 days of age. The oxidative stability, evaluated by thiobarbituric acid reactive substances (TBARS) values, was determined after 30, 90, 120 and 150 days of storage at -20°C. There were no statistical differences (P>0.05) in average daily gain (1.85 ± 0.111 g) or feed conversion ratios (2.29 ± 0.397) among dietary groups. TBARS values increased significantly (P<0.05) with increasing time of storage (basal diet: day 30 = 1.71 ± 0.51; day 150 = 4.89 ± 0.51), but decreased significantly (P<0.05) with increasing vitamin E levels (day 150: basal = 4.89 ± 0.51; 100 mg / kg = 1.09 ± 0.27). Experiment 2 was carried out with day-old broiler chicks to evaluate the effect of five concentrations of vitamin E (0, 40, 80, 120 and 160 mg atocopheryl acetate / diet) on their performance and the oxidative stability of their refrigerated carcasses. The experimental diets were fed from day-old to 42 days of age. The oxidative stability, evaluated by TBARS values, colour deterioration and microbiological stability were determined after 0, 4, 8, 10 and 12 days of storage at 4°C. Fatty acid analysis was done on the samples of days 0 and 12. There were no statistical differences (P>0.05) in average daily gain (1.88 ± 0.117 g) or feed conversion ratios (2.37 ± 0.467) among dietary groups. TBARS values increased significantly (P<0.05) with increasing time of storage, but decreased significantly (P<0.05) with increasing vitamin E levels. There were no statistical differences (P>0.05) in colour measurements for L* (44.97 ± 0.662), a* (5.23 ± 0.315) or b* (12.76 ± 0.321) values between treatments. Microbiological counts increased significantly (P<0.05) over time with vitamin E concentration showing no effect. There were no statistical differences (P>0.05) for any of the fatty acid groups measured (SFA: Day 0 = 26.1 ± 1.13%, Day 12 = 26.1 ± 1.17%; MUFA: Day 0 = 41.4 ± 1.46%, Day 12 = 40.2 ± 2.28%; PUFA: Day 0 = 32.4 ± 1.95%, Day 12 = 33.8 ± 2.52%) among dietary groups. Similarly, none of the fatty acids showed statistical significant (P>0.05) concentration changes over time. There were no statistical differences (P>0.05) in pH (6.01 ± 0.206) among dietary groups. / AFRIKAANSE OPSOMMING: Lipiede is steeds een van die mees belangrike voedingstowwe wat deur braakuikens benodig word. Die groeiende bewuswording dat sekere Westerse gemeenskappe 'n te hoë verhouding van n-6/n-3 poli-onversadigde vetsure in hul dieet het, is direk relevant vir braaikuikenvoeding en lipiedmetabolisme. Betekenisvolle hoeveelhede n-3 polionversadigde vetsure is geïnkorporeer in die belangrikste hoendersnitte, met die gevolg dat die produksie van braaikuikenvleis met hoë n-3 poli-onversadigde vetsure voordelig is vir die braaikuikenindustrie en geag word 'n meer "gesonde" beeld te hê. Ongelukkig is sodanige braaikuikenvleis redelik vatbaar vir oksidatiewe bederf, en oksidasie bepaal dikwels die rakleeftyd van hoendervleisprodukte. Die byvoeging van a-tokoferol (vitamine E) by braaikuikendiëte is 'n effektiewe manier om die oksidatiewe stabiliteit van braaikuikenvleis te verbeter. Verhoogde a-tokoferol vlakke in braakuikenvoere verhoog die weefselkonsentrasie wat verhoogde stabiliteit van die membraanstrukture en derhalwe moontlike verhoogde oksidatiewe stabiliteit van braakuikenvleis en -produkte tot gevolg het. Drie ondersoeke is onderneem by Mariendahl Pluimvee Navorsingstasie te Stellenbosch. Die braakuikens is aangehou in 1 x 0.4 x 0.5m hokke in braaikuikenhuise. In al die proewe is dagoud kuikens gebruik, behalwe eksperiment 1 waar drieweek oue kuikens gebruik is. Aan die einde van proewe 2 en 3 is die ses-week oue braaikuikens geslag en die karkasse voorberei vir analise. Eksperiment 1: braaikuikens. Die ware metaboliseerbare energie waarde van Canola voergraadolie (CAO) en Famarol voergraadolie (FAO), Metaboliseerbare energie van Canola voergraadolie en Famarol voergraadolie vir gekorregeer vir stikstof retensie (WMEn), is by wyse van proewe op 21 dae oue braaikuikenhaantjies bepaal deur van die balansrnetode gebruik te maak. Die proewe is tweemaal herhaal vir verhoogde akkuraatheid, met die gebruik van verskillende monsters van die twee olies vanaf dieselfde bron. Die olies is in twee verhoudings met 'n basale diëet gemeng om die proef dieet te vorm, nl. 100% Basaal; 96% Basaal: 4% Olie en 92% Basaal: 8% Olie. Die balans proewe het 3 dae geduur na afloop van 'n aanpassingsperiode van 4 dae. Die WMEn waardes van CAO, bepaal deur middel van regressie analise, het nie betekenisvol verskil (P>0.05) tussen eksperimente 1 en 2 nie. Die waarde van eksperiment 3 was betekenisvol hoër (P<0.05) as die van die eerste twee eksperimente. Die WMEn waardes van FAO het ook nie betekenisvol verskil (P>0.05) tussen eksperimente 1 en 2 nie, maar die waarde vir eksperiment 3 was betekenisvol hoër as dié van eksperiment 1. Die WMEn waardes van COA het betekenisvol verskil (P< 0.05) van dié van FAO vir al die eksperimente (exp. 1: 30.6 ± 0.399 MJ/kg vir CAO vs. 25.9 ± 0.441 MJ/kg vir FAO; expo 2: 31.0 ± 0.633 MJ/kg vir CAO vs. 26.1 ± 0.668 MJ/kg vir FAO: expo 3: 32.1 ± 0.867 MJ/kg vir CAO vs. 27.1 MJ/kg vir FAO). Eksperiment 2: Die invloed van verskeie rantsoen n-6/n3 vetsuurverhoudings op die produksie en liggaamsamestelling van braaikuikens. Die rantsoeneffek van verskeie kombinasies Canola voergraadolie (CAO, 'n hoë vlak van C18:3n-3 en monoonversadigde vetsure) en Famarol voergraadolie (FAO, 'n hoë vlak van 18:2n-6 en versadigde vetsure) op die weefselvetsuursamestelling is bestudeer in braaikuikenkarkasse en abdominale vetneerlegging. Die kuikens is van dagoud to op ses-weke ouderdom een van ses diëte gevoer met die volgende samestellings: 100% FAO, 80% FAO-20% CAO, 60% FAO - 40%CAO, 40% FAO - 60% CAO, 20% FAO - 80% CAO, 100% CAO. Daar was geen statistiese verskil tussen die rantsoengroepe (P>0.05) in die gemiddelde daaglikse toename (1.71 ± 0.059 g) of die voeromsetverhoudings (1.97 ± 0.051) nie. Geen statistiese verskil (P>0.05) is gevind in die chemiese samestelling van die karkasse vir vog (66.20 ± 0.112 %), proteïn (17.63 ± 0.484 %), lipied (15.92 ± 1.507 %) en as (0.95 ± 0.115 %) inhoud tussen die rantsoen groepe nie. Geen statistiese verskille (P>0.05) is gevind in die chemiese samestelling van die abdominale vetneerlegging vir vog (28.77 ± 0.112 %), proteien (3.03 ± 0.484 %), lipied (63.32 ± 9.789 %) en as (0.45 ± 0.135 %) inhoud onder die rantsoengroepe nie. Met die verhoging in die rantsoen CAO vlakke het die persentasie van C18:2n-6 en C20:4n-6 in die karkasse verminder met 1.78 % en 0.35 % respektiewelik, terwyl C18:3n-3 en langer ketting n-3 vetsure soos C20:5n-3 en C22:6n-3 respektiewelik met 2.25 %, 0.1 % en 0.67 % verhoog het. Dieselfde tendens is opgemerk in die abdominale vetneerlegging waar C18:2n-6 en C20:4n-6 afgeneem het met 1.55 % en 0.98 % respektiewelik met die verhoging van rantsoen CAO, terwyl C18:3n-3, C20:5n-3 en C22:6n-3 verhoog het met 2.13 %, 0.45 % en 0.95 % respektiewelik. Die n- 3/n-6 verhouding in die karkasse en abdominale vetneerlegging het verhoog met 0.16 % en 0.19 % respektiewelik met die verhoging van die rantsoen CAO. Die resultate toon onomwonde aan dat rantsoen CAO verryk met c-Iinoletensuur, verlaag versadigde vetsure in braaikuikenkarkasse en -adbdominale vetneerleggings met 4.88 % en 10.63% respektiewelik, terwyl die mono-onversadigde vetsure met 3.87 % en 7.25 % respektiewelik verhoog word en polionversadigde vetsure met 1.02 % en 2.38 % respektiewelik verhoog word. Eksperiment 3: Die invloed van vitamine E op die produksie van braaikuikens en die oksidatiewe stabiliteit, kleur, mikrobiologiese stabilitiet, vetsuursamestelling en pH van braaikuikenvleis gedurende verkoelde en bevrore berging. Eksperiment 1 is uitgevoer met 220 dagoud braaikuikens ten einde die effek van elf konsentrasies van vitamine E (0, 20, 40, 60, 80, 100, 120, 140, 160, 180 en 200 mg a-tokoferyl acetaat / kg voer) op hul produksieprestasie en die oksidatiewe stabiliteit van hul gevriesde braakuikenkarkasse te evalueer. Die diëte met vitamine E vlakke 0 tot 100 mg is vanaf dagoud tot 42-dae-ouderdom gevoer, terwyl die diëte met vitamine E vlakke van 120 tot 200mg gevoer is vanaf 21 tot 42- dae-ouderdom. Die oksidatiewe stabiliteit, soos geëvalueer deur tiobarbituriese suur reaktiewe stowwe (TBARS) waardes, is bepaal na 30, 90, 120 en 150 dae van berging teen -20°C. Daar was geen statistiese verskille (P>0.05) in die gemiddelde daaglikse toename (1.85 ± 0.111 g) of voeromsetverhoudings (2.29 ± 0.397) tussen die rantsoengroepe nie. TBARS waardes het betekenisvol toegeneem (P<0.05) met die verhoging in bergingsperiode, maar het betekenisvol afgeneem (P<0.05) met verhoogde vitamine E vlakke. Eksperiment 2 is uitgevoer met dagoud braaikuikens ten einde die effek van vyf konsentrasies van vitamine E (0, 40, 80, 120 and 160 mg a-tokoferyl acetaat / kg voer) op hul prestasie en die oksidatiewe stabiliteit van hul verkoelde karkasse te evalueer. Die eksperimentele diëte is gevoer vanaf dagoud tot 42- dae-ouderdom. Die oksidatiewe stabiliteit, geëvalueer deur middel van TBARS waardes, kleur afname en mikrobiologiese stabiliteit is bepaal na 0, 4, 8, 10 en 12 dae van berging teen 4°C. Vetsuuranalises is gedoen op die monsters van dae 0 en 12. Daar was geen statistiese verskille (P>0.05) in die gemiddelde daaglikse toename (1.88 ± 0.117 g) of voeromsetverhoudings (2.37 ± 0.467) tussen die rantsoengroepe nie. TBARS waardes het betekenisvol verhoog (P<0.05) met die verlengde bergingsperiode, maar het betekenisvol afgeneem (P<0.05) met verhoogde viatmine E vlakke. Daar was geen statistiese verskille (P>0.05) in kleur metings vir L* (44.97 ± 0.662), a* (5.23 ± 0.315) of b* (12.76 ± 0.321) waardes tussen behandelings nie. Mikrobiologiese tellings het betekenisvol verhoog (P<0.05) oor tyd met die vitamine E konsentrasie wat geen effek getoon het nie. Daar was geen statisties betekenisvolle verskille (P>0.05) vir enige van die vetsuurgroepe tussen die behandelings nie. Soortgelyks het geen van die vetsure statisties betekenisvolle (P>0.05) konsentrasieveranderings oor tyd aangetoon nie. Daar was geen statistiese verskil (P>0.05) in die pH (6.01 ± 0.206) tussen die rantsoengroepe nie.

O presente estudo teve como objetivo avaliar a utilização de campo magnético pulsado (CMP) de baixa intensidade na preservação da qualidade microbiológica, cor e estabilidade oxidativa de carne bovina moída durante armazenamento aeróbio refrigerado. Amostras moídas de peixinho bovino (músculo Supraspinatus) foram expostas a CMP por 2 horas às frequências de 1, 30 ou 60 Hz ou, em outra etapa, expostas a CMP de 1 Hz de frequência por 2 horas ou continuamente por 12 dias. Amostras controle não foram expostas ao CMP. As amostras foram armazenadas a 4ºC por até 12 dias, e avaliadas a cada seis dias por meio de análise microbiológica de contagem total de bactérias mesófilas aeróbias, e a cada dois dias por meio de análises físico-químicas e bioquímicas: pH, cor instrumental (escala CIELAB), mioglobina e oxidação lipídica. A exposição ao CMP de 1 Hz por 2 horas reduziu a contagem de mesófilos aeróbios com relação ao controle em 1,3 ciclos logarítmicos no 12º dia de armazenamento refrigerado. Os conteúdos de metamioglobina das amostras expostas por 2 horas ao CMP, independente da frequência de pulso, foram significativamente menores com relação ao controle no 6º dia de armazenamento refrigerado. Os demais parâmetros de qualidade não sofreram alteração significativa com relação ao controle durante o armazenamento e não foi verificado efeito das diferentes frequências de CMP. Conclui-se que campo magnético pulsado de baixa intensidade (ordem de mili Tesla) apresenta potencial para ser utilizado como tecnologia inovadora, em combinação com a refrigeração, na preservação de carnes frescas. Todavia, mais estudos são necessários para melhor entendimento dos mecanismos de ação de campo magnético, principalmente em alimentos. / This study aimed to evaluate the use of low intensity pulsed magnetic field (PMF) in the preservation of microbiological quality, color and oxidative stability of ground beef during aerobic refrigerated storage. Ground beef samples of chuck tender (Supraspinatus muscle) were exposed to PMF for 2 hours at frequencies of 1, 30 and 60 Hz or, in another step, they were exposed to a 1 Hz PMF for 2 hours or continuously for 12 days. Control samples were not exposed to PMF. Samples were stored at 4ºC for up to 12 days, and evaluated every six days through microbiological analysis of total aerobic mesophilic bacteria count, and every two days through physicochemical and biochemical analysis of pH, instrumental color (CIELAB scale), myoglobin and lipid oxidation. Exposure to 1 Hz PMF for 2 hours reduced the growth of aerobic mesophiles in relation to the control by 1.3 logarithmic cycles in the 12th day of refrigerated storage. Metmyoglobin content of samples exposed to the PMF for 2 hours, regardless of the pulse frequency, were significantly lower compared to the control in the 6th day of refrigerated storage. The other quality parameters did not change significantly during storage compared to the control and it was not observed effect of different PMF frequencies. We concluded that low intensity pulsed magnetic field (order of mili Tesla) has the potential to be used as innovative technology, in combination with refrigeration, in fresh meat preservation. However, more studies are needed to better understand the mechanisms of action of magnetic field, mainly in foods.

Um Leistungsniveau, systematische Effekte und phänotypische Korrelationen zu schätzen, wurden bei 276 Weidekälbern verschiedener Genotypen aus der Mutterkuhhaltung (Material I) Merkmale der Fleischleistung und der Fleisch¬qualität erfasst und ausgewertet. Neben den Identitäts- und Lebensdaten der Tiere wurden die folgenden Merkmale der Fleischleistung einbezogen: Alter beim Schlachten, Lebendgewicht, Lebenstagszunahme, Schlachtkörper¬gewicht, Nettozunahme sowie die Komponenten der Handelsklasse, also Fleischigkeitsklasse und Fettgewebeklasse. / In order to estimate performance level, systematic effects and phenotypic correlations, characteristics of meat performance and meat quality were recorded and analysed in 276 weaning calves of different genotypes from cow-calf operations (material I). In addition to identity and basic life data, the following characteristics of meat performance were included: age at slaughter, live weight, daily gain, carcass weight, net gain as well as the components of the carcass grade, grade for meatiness and grade for fat¬ness. The following characteristics of meat quality were measured on the meat probes 48 hours and 14 days resp. after slaughter: pH-value (pH1, pH2), meat colour with lightness L* (L*1, L*2) redness a* (a*1, a*2) and yellowness b* (b*1, b*2), Warner-Bratzler shearforce raw (WBS1, WBS2) and cooked (WBS3) as well as intramuscular fat content (IMF).

O presente trabalho de pesquisa foi conduzido no período de outubro de 2007 a março de 2008 na Estação de Avaliação de Suínos em Tanquinho, Piracicaba SP, no Frigorífico BRESSIANI®, localizado na cidade de Capivari SP, e as avaliações bioquímicas, químicas, quantidade e qualidade de carne foram realizadas no mês de março a abril de 2008, no Centro de Pesquisa e Desenvolvimento de Carnes do Instituto de Tecnologia de Alimentos, localizado na cidade de Campinas SP. Neste experimento foram testados métodos de castração de suínos objetivando avaliar a incidência do odor de macho inteiro, causado pela androstenona e escatol, presentes no tecido adiposo dos suínos machos, composição corporal e da carcaça. Entre os métodos de castração de suínos machos existentes, foram avaliados o cirúrgico e imunológico. O primeiro consistiu na remoção cirúrgica das gônadas do leitão entre 3 a 5 dias de vida e o segundo na aplicação de duas doses da forma modificada do Fator de Liberação das Gonadotropinas (GnRF) em um sistema coadjuvante de baixa reatividade, sendo a primeira dose aplicada nos animais com 15 semanas e a segunda dose com 19 semanas de idade. Após duas semanas da segunda dose foram coletadas amostras de sangue para avaliação de testosterona através de radioimunoensaio. No momento do abate foi realizada a coleta de parte do tecido adiposo para análise de androstenona e escatol. Nas meias carcaças esquerdas foram avaliadas a qualidade de carne (pH, temperatura, capacidade de retenção de água, perda por exsudação e cor) e a quantidade (medidas lineares das carcaças e rendimentos dos cortes anatômicos). A vacinação dos animais contra o GnRF demonstrou sua eficiência em controlar os compostos responsáveis pelo odor sexual (androstenona e escatol) e em manter os níveis de testosterona comparáveis aos animais castrados cirurgicamente. A imunocastração melhorou o desempenho zootécnico e contribuiu para aumentar a quantidade de carne por animal (4,84 kg), diminuir a de gordura (1, 54 kg) e acrescentar mais carne nos cortes de maior valor comercial, como pernil (1060 g, p < 0,05), carre(400 g, p > 0,05), a barriga (840 g, p < 0,05) e paleta (1460 g, p < 0,05), que representa uma vantagem econômica para a indústria da carne, pois atende os mercados de carne fresca e de produtos industrializados (cozidos e embutidos). Em relação à avaliação sensorial foram constatadas diferenças significativas (p < 0,05) para todos os atributos sensoriais avaliados em favor dos suínos imunocastrados quando comparados com os castrados cirurgicamente. Quanto à preferência, os bifes cozidos de lombo dos suínos imunocastrados obtiveram melhor preferência (66%) em comparação com os castrados cirurgicamente (34%). A intenção de compra também foi em favor dos suínos imunocastrados e refletiu os resultados dos testes de preferência e de aceitação. A maioria dos consumidores (74,8%) provavelmente (20,2%) ou certamente (54,6%) compraria a carne dos suínos imunocastrados e somente 58,4% dos consumidores provavelmente (25,2%) ou certamente (33,2%) compraria a carne dos suínos castrados cirurgicamente. A gordura total encontrada no lombo nesse experimento foi 14.67 e 12.67 g/100g para o grupo dos suínos castrados cirurgicamente e imunocastrados, respectivamente. O rendimento de cocção e os valores da força máxima de cisalhamento (Warner - Bratzler) dos suínos castrados cirurgicamente e imunocastrados não foram estatisticamente diferentes (p > 0,05) enquanto que a cor instrumental (L*, a* e b*) apresentou diferença estatística (p < 0,05) na sua composição para os tratamentos estudados. Os resultados desse trabalho permitem dizer que a imunocastração demonstrou ser eficiente em prevenir o odor sexual bem como em melhorar o desempenho zootécnico e qualidade de carcaça quando comparada com a castração cirúrgica. Quanto à qualidade de carne dos suínos imunocastrados ficou evidenciado que essa tecnologia pode melhorar os atributos sensoriais e outras características de qualidade realizadas nessa pesquisa. / The present study was carried out from October 2007 to March 2008 at the Pig Evaluation Station in Tanquinho, located in Piracicaba city, São Paulo state, in the BRESSIANI® abattoir, located in Capivai, city, São Paulo state, and the biochemical, chemical, meat quantity and meat quality assessments were carried in March 2008, at the Meat Center for Research and Development in the Institute of Food Technology, located in Campinas city, São Paulo state. In this experiment were tested castration methods applied in pigs to evaluate the incidence of the boar taint, caused by androstenone and skatole located in the fat of boars, carcass composition and meat quality. The castration methods tested were physical and immunological. In the first one pig gonads were removed physically at the age 3 to 5 days and the last one the pigs were immunocastrated (two doses, 15 and 19 weeks of age) against the modified factor gonadotropin-releasing (GnRF). After two weeks of the second dose blood samples were taken to evaluate testosterone using radioimmunoassay. At the slaughter level a portion of backfat was collected to assess androstenone and skatole. Meat quality (pH, temperature, water holding capacity, loss of weeping and color) and quantity (linear measurements of carcasses and anatomical cuts yield) were performed at left carcass side. Vaccination of animals against GnRF demonstrated its effectiveness in controlling the boar taint compounds (androstenone and skatole) and to maintain the levels of testosterone comparable to physically castrated animals. The immunocastration improved growth performance and contributed to increase the total meat quantity per animal (4.84 kg), reducing the fat (1, 54 kg) as well as added more meat in cuts of higher commercial value, such as ham (1060 g, p < 0.05), loin (400 g, p > 0.05), belly (840 g, p < 0.05) and shoulder (1460 g, p < 0.05), which represents an economic advantage for the meat industry since reaches booths markets fresh and processed meats products (sausage and cooked). Regarding the sensory evaluation were found significant differences (p < 0.05) for all sensory attributes evaluated in favor ofimmunocastrated pigs when compared with physically castrated. The preference test applied to cooked sirloin steak from immunocastrated pigs indicated better preference (66%) compared with physically castrated (34%). The panelists intent to purchase was also in favor of the immunocastrated treatment and confirmed the results from the preference and acceptance tests. The majority (74.8%) of the consumers probably (20.2%) or certainly (54.6%) would buy meat from the immunocastrated pigs compared to 58.4% of the consumers who would probably (25.2%) or certainly (33.2%) would buy meat from physically castrated pigs. Loin total fat content found in the experiment was 14.67 and 12.67 g/100g for the physical and immunocastrated groups respectively. The immunocastrated group contained 11.2% less fat than the surgical castrates. Cooking yields and peak Warner-Bratzler shear force values from physically castrated and immunocastrated pigs were not statistically different (P > 0.05) while statistically significant differences (p < 0.05) in the brightness (L*), redness (a*) and yellowness (b*) parameters were observed between the two treatments. From the above considerations it can be said that immunocastration shows very good potential for pre-venting boar taint. Pain and stress associated with physical castration can thus be avoided. It was also demonstrated that immunocastrated pigs improved some meat quality aspects evaluated. Sensory, total fat content and color were the main factors affected by immunocastration while cooking loss and instrumental tenderness had no remarkable changes. The consumers classified meat from immunocastrated pigs significantly better than physically castrated pigs as far as acceptability, preference and purchase intention are concerned. Thus, immunocastration results in production of animals with high meat quality in the carcass and still capitalizes on the growth, feed efficiency and carcass leanness of boars up to the point of immunocastration.

A maioria dos bovinos criados sob condições brasileiras normalmente sofre alguma restrição alimentar, que exerce efeitos negativos sobre o sistema de produção, implicando em perdas econômicas e de qualidade. Com o objetivo de reduzir esses problemas o confinamento de bovinos com dietas com alta percentagem de grãos é uma alternativa. No entanto, especialmente em relação a raça Nelore, maioria do rebanho brasileiro, a resposta a dietas com alta percentagem de grãos (amido) apresenta resultados variados. Diferentes formas de processamento dos grãos, bem como o aumento da densidade energética da dieta através da adição de gordura também têm sido estudadas. O objetivo deste trabalho foi avaliar o efeito do fornecimento de dietas contendo milho grão seco, milho grão úmido e sais de cálcio de ácidos graxos (SCAG) sobre o desempenho características de carcaça e perfil de ácidos graxos do músculo Longissimus dorsi de novilhos Nelore em fase de terminação, bem como utilizar medidas de ultra-sonografia para estimar rendimento da porção comestível após o abate. O fornecimento de milho grão úmido não alterou o ganho médio diário, reduziu a ingestão de matéria seca e tendeu a diminuir a conversão alimentar. A concentração de ácidos graxos polinsaturados, a relação polinsaturado:saturado, ácidos graxos n-6 e a relação n-6:n-3 foi maior nos animais que receberam as dietas contendo milho úmido. Os SCAG não influenciaram o ganho médio diário, aumentaram a ingestão de alimento, sem efeito sobre a conversão alimentar. Os SCAG aumentaram a percentagem de ácidos graxos n-6, bem como a relação n-6:n-3. As equações para estimativa do peso dos cortes comerciais utilizando medidas de ultra-som apresentaram acurácia semelhante àquelas utilizando as medidas obtidas diretamente na carcaça após o abate / The majority of the beef cattle raised under Brazilian conditions is periodically submitted to feed restrictions, which have negative effects to the production system, causing economic and qualitative losses. Feedlot finishing beef cattle is one alternative to avoid these losses. However, the Brazilian herd is composed mostly of cattle from the Nellore breed, which frequently do not have a good performance with diets with a high proportion of grains (starch). Several grain processing ways or increasing energy density through the inclusion of fat have been studied to improve animal performance. The aim of this study was to evaluate the effect of diets with dry corn grain, high moisture corn grain and calcium salts of fatty acids (SCAG) on the performance, carcass characteristics and fatty acids profile of the Longissimus dorsi muscle of feed lot finished Nellore steers, as well as to utilize ultrasound measurements to evaluate the edible portion after slaughter. Feeding high moisture corn had no effect on weight gain, but decreased dry matter intake and showed a tendency to decrease feed conversion. High moisture corn diets increased polyunsaturated fatty acids and the ratio of polyunsaturated to saturated fatty acids and also had greater proportion o n-6 and n-6 to n-3 ratio. Feeding SCAG did not affect average daily gain, increased feed intake without effect on feed conversion. The SCAG increased n-6 percentage and the n6 to n3 ratio. The equations to estimate the weight of the retail products using ultrasound measurements showed accuracy similar to those equations using measurements obtained in the carcass after slaughter

This study was developed in order to explore chromosomal regions associated with carcass and meat traits in Nellore cattle breed, identifying metabolic and genetic pathways related to its characteristics expression, as well as generate additional phenotypes for future genome association studies, in order to fully describe parameters related to final product quality. Thereunto, 995 bulls were genotyped for more than 770,000 single nucleotide polymorphisms (SNPs), were evaluated for body weight at birth, weight gain at weaning and yearling, conformation, finishing precocity and muscling at weaning and yearling. These traits are correlated, therefore, genomic mapping method were applied in order to identify pleiotropic regions. Results highlighted previously described genomic regions associated to beef cattle weight gain and growth traits, particularly PLAG1 gene, sheltered by the most significantly associated marker region, which in other studies were associated to weight, height and sexual precocity in Nellore breed. To evaluate carcass and meat quality traits, 576 young bulls were evaluated for hot carcass weight, ribeye area, fat thickness, pH 24 hours after slaughter and color parameters (L*, a*, b*), for shearing force, dripping and cooking loss, evaluations were performed for different maturation times (7, 14 and 21 days). Animals were genotyped on two platforms, Illumina&reg; BovineHD BeadChip (HD) and Bovine GeneSeek&reg; Genomic Profiler &trade; HD Illumina Infinium&reg; (GGP). Animals genotyped at a lower density (GGP) were imputed to high density chip (HD). Shear force, dripping and cooking loss measures which relates to meat tenderness, were associated to cytoskeleton structure and proteolytic enzymes activity, pointing to serine/serpin enzyme complex as main candidates for regulate proteolysis and muscle fiber structure degradation. Were performed an evaluation of Longissimus thoracis et lumborum intramuscular fat content of 148 animals. It was approached by a human health perspective where samples received a classification regarding fatty acids effects on human organism (\"beneficial\", \"evil\" or \"neutral\"), as well as provided phenotypic information for future genome association studies. The identification of 42 fatty acids and 16 indexes, generated detailed information on these animals\' meat fat composition. Principal component analysis (PCA) results showed that large variation proportion between samples fat composition occurs due to expression differences among desaturase and elongase enzymes. Thus, it is expected that generated data, information and knowledge hereby, can assist animal breeding programs to improve Brazilian herds according meat chain interests. / O presente trabalho foi desenvolvido com o objetivo de explorar regiões cromossômicas associadas à características de carcaça e carne em bovinos da raça Nelore, explorar suas funções em vias metabólicas e gênicas relacionadas às manifestações dessas características, assim como gerar novos fenótipos para futuros estudos de associação genômica, com vistas a descrever, de forma completa, as características relacionadas à qualidade do produto final. Para isso, 995 animais machos não castrados, genotipados para mais de 770.000 marcadores de polimorfismos de nucleotídeo único (SNP), foram avaliados quanto ao peso corporal ao nascimento, ganho de peso à desmama e ao sobre ano, conformação, precocidade de terminação e musculosidade à desmama e ao sobre ano. Como estas características são correlacionadas, foram aplicadas metodologias de mapeamento genômico com o objetivo de identificar regiões pleiotrópicas. Os resultados destacaram regiões do genoma bovino que contêm genes descritos por influenciarem em características de crescimento e ganho de peso nestes animais, com destaque para o gene PLAG1, pertencente à região do marcador mais significativo associado aos fenótipos, anteriormente associado ao peso, altura e precocidade sexual em animais dessa raça. Para acessar atributos de qualidade de carcaça e carne, 576 machos não castrados foram avaliados quanto ao peso de carcaça quente, área de lombo, espessura de gordura subcutânea, pH após 24 horas do abate, cor (L*, a*, b*) e perdas de peso por exsudação e cozimento e força de cisalhamento em diferentes tempos de maturação (7, 14 e 21 dias). Os animais foram genotipados em duas plataformas, Illumina&reg; BovineHD BeadChip (HD) e GeneSeek&reg; Genomic Profiler Bovine HD&trade; Illumina Infinium&reg; (GGP), sendo os genótipos deste último imputados para o conjunto de maior densidade. As avaliações de perdas de peso por exsudação e cozimento e força de cisalhamento, utilizada para mensurar maciez, revelam a influencia da estrutura do citoesqueleto e da ação das enzimas proteolíticas, apontando o complexo enzimático serinas/serpinas como candidato na regulação do processo de proteólise e degradação da estrutura da fibra muscular. Foi realizada avaliação dos ácidos graxos no músculo Longissimus thoracis et lumborum de 148 animais com vistas à classificação das amostras quanto aos efeitos esperados no organismo humano (\"benéfico\", \"maléfico\" ou \"neutro\"), assim como prover informação fenotípica para futuros estudos de associação genômica. A identificação de 42 ácidos graxos e 16 índices gerou informação detalhada sobre a gordura presente na carne destes animais, sendo observado, por análise de componentes principais (PCA), que a maior variação entre a composição das amostras avaliadas parece ser em decorrência da diferença de expressão das enzimas elongases e dessaturases. Dessa forma, espera-se que os dados, informações e conhecimento gerados por este trabalho, possam auxiliar os programas de melhoramento genético animal a aprimorar o rebanho brasileiro segundo características de interesse da cadeia produtiva de carne.

Submitted by Ubirajara Cruz (ubirajara.cruz@gmail.com) on 2017-03-29T16:36:43Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_Sandra_Moura.pdf: 2502419 bytes, checksum: 5bd1b41befa6c6980cfc4179c0e6ae17 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-04-05T17:58:40Z (GMT) No. of bitstreams: 2 Tese_Sandra_Moura.pdf: 2502419 bytes, checksum: 5bd1b41befa6c6980cfc4179c0e6ae17 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-04-05T17:58:40Z (GMT). No. of bitstreams: 2 Tese_Sandra_Moura.pdf: 2502419 bytes, checksum: 5bd1b41befa6c6980cfc4179c0e6ae17 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-04-30 / O estresse é um tema de relevante importância tanto para a área humana quanto animal. Animais produtores de carne são submetidos a diferentes fatores pré-abate. Esses fatores estressantes podem causar alterações fisiológicas que conduzem a um efeito prejudicial na qualidade final da carne. No Brasil, o mercado da carne ovina apresenta-se em ascensão, especialmente nos países em desenvolvimento, onde ocorre o crescimento econômico dos consumidores e o aumento da demanda. Neste contexto, realizou-se uma revisão bibliográfica dos últimos 40 anos, a qual aborda o manejo pré-abate, aspectos do comportamento e suas consequências na qualidade final da carne. Em um segundo capítulo, realizou-se um estudo com os objetivos de: (1) Descrever e padronizar a curva de pH da transformação em carne dos músculos Triceps brachii, Longissimus dorsi e Biceps femoralis de ratos submetidos a condições normais de criação desde a eutanásia até 24 horas post-mortem; (2) determinar se a análise em cada músculo altera significativamente a curva de pH; (3) determinar se o estresse pela contensão dos ratos no período ante mortem causa alterações qualitativas na carne e se afeta o tempo e os valores de pH necessários para a transformação do músculo em carne. Para a determinação da curva de pH muscular foram utilizados 12 ratos machos da linhagem Wistar, os animais sofreram eutanásia e as carcaças foram colocadas sob refrigeração para as aferições do pH muscular. Outro grupo de 12 animais foi submetido ao estresse por contensão e após foi realizada a eutanásia, seguido das avaliações de pH. Os resultados indicam que: (1) os valores de queda do pH muscular post mortem de ratos apresentam um ritmo semelhante às espécies comerciais; (2) os valores médios de pH muscular nos 3 grupos musculares não apresentam diferenças significativas em todos os períodos analisados; (3) as médias de pH muscular apresentam diferenças significativas da hora 0 até 6 horas após o abate, quando o valor mínimo de pH muscular é determinado. Assim, conclui-se, embora sejam conhecidos diferentes fatores pré-abate causadores de alterações fisiológicas que culminem com efeitos prejudiciais para a qualidade final da carne, ainda existem poucos métodos confiáveis, de fácil execução e não invasivos para detectar estresse em animais, padronizados até o momento. Os ratos são um modelo promissor para detectar alterações post-mortem, pois o decréscimo do pH muscular segue os valores e tempo semelhantes ao que ocorre nas espécies comerciais. / Stress is a topic relevant importance to both human and animal area. Animal meat producers are subjected to different pre-slaughter factors from the production unit to the slaughterhouse. These stressors factors to animals may cause physiological changes leading to an adverse effect on the final quality of the meat. In Brazil, in last years, sheep meat is a growing market, especially in developing countries, where economic growth more abundant, and increasingly demanding, consumers. In this contest, we conducted a literature review in the last 40 years, that addresses to slaughter handling of these animals, aspects of ovine behavior, and its consequences on final meat quality. In the second chapter, there was a study with the objectives of (1) to describe and standardize the pH curve transformation into meat muscle Triceps brachii, Longissimus dorsi and Biceps femoralis of rats subjected to normal breeding conditions from euthanasia to 24 hours post-mortem; (2) to determine whether the analysis in each muscle modify significantly the pH curve; (3) to determine whether the stress by rats restraining in the ante-mortem period cause qualitative changes in meat and affects the time and pH values for the transformation of muscle in meat. For the determination of muscle pH curves were used 12 male Wistar rats, and animals were euthanized and the carcasses were placed under refrigeration for measurements of pH. Another group of 12 animals was subjected to stress by restraining and after euthanasia was performed the pH evaluations. The results indicate that: (1) the post-mortem muscle pH values in rats show a downward trend similar commercial species; (2) the average values of muscle pH in the three muscle groups do not differ significantly in all the analyzed periods; (3) The medium muscle pH are significant differences between time 0 to 6 hours after slaughter, when the minimum value is determined. Thus, we conclude that although known different pre-slaughter factors that may cause physiological changes that culminate with detrimental effects on the final quality of the meat, there are few reliable methods, easy to perform and non-invasive to detect this stress in animals were standardized until now. Rats are a promising experimental model to detect post-mortem changes, because the decrease in the muscle pH follows the values and time similar to what happens to the commercial species.