• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 25
  • 11
  • 10
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • Tagged with
  • 54
  • 54
  • 54
  • 27
  • 19
  • 19
  • 17
  • 15
  • 14
  • 14
  • 12
  • 11
  • 9
  • 9
  • 8
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.


SADIK, HAITHAM LOTFY. January 1986 (has links)
An experiment was conducted with laying hens to evaluate the effects of added lysine, methionine and tallow on laying hen performances. Twenty-four treatments were obtained as a result of supplementing the basal diets, which contained either 13.86% or 13.5% protein, with 4 levels of synthetic L-lysine Hcl and with 3 levels of DL-methionine. Each treatment was fed to 5 neplicates of four birds each for ten 28-day periods. Tallow was added at a level of 4% to the 13.5% protein diet. Significant improvements were obtained in egg production and in egg mass as a result of lysine and methionine supplementation. However, 4% added tallow significantly decreased egg production and egg mass. On the other hand, tallow exerted positive effects upon the efficiency of feed utilization only when the diets were adequate in both lysine and TSAA. Three response criteria were used to measure the daily intake of lysine and total sulfur amino acids which are methionine and cysteine (TSAA) required by laying hens; percent egg production, egg mass, and plasma free lysine and TSAA levels. The pattern of response suggested that the dietary lysine requirements were 718 and 709 mg/hen/day for egg production and egg mass respectively; and the dietary TSAA requirements were 616 and 626 mg/hen/day for egg production and egg mass respectively. Multiple regression analysis, which related the intake of these amino acids with hen performances showed numerical, but non-significant, differences than the above requirement values. Using plasma free lysine and TSAA as criteria, the requirements for lysine and TSAA obtained from regression analysis were 674.8 and 561.6 mg/hen/day respectively. Feed intakes and protein intakes were not significantly affected by either lysine or methionine supplementation. However, 4% added tallow significantly decreased feed intakes and protein intakes.


Valencia, Mauro Eduardo Fernando, 1949- January 1978 (has links)
No description available.

Comparison of feeding various sources of energy and protein on performance of broiler chicks with and without an anthelmintic

Abdul-Hamad, Sabah-N. January 1978 (has links)
Call number: LD2668 .T4 1978 A23 / Master of Science

Actual and predicted performance of broiler chickens

Van Niekerk, S. J. (Sarel Johannes) 03 1900 (has links)
Assignment (MPhil)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The aim of this study was to evaluate the performance and profitability of different dietary specifications for broiler chickens slaughtered at 35 days of age. Two trials were performed to evaluate different production parameters. The results of these trials were compared to the predicted results of the EFG broiler model. No carcass data were available for the two trials mentioned above. Therefore, in order to evaluate the accuracy of the broiler model when predicting carcass characteristics, two published data sets (Leeson et al., 1996a) were used. Predicted and actual values were compared, evaluated and discussed. Two broiler trials were performed. In Trial One the amino acid density decreased throughout the range of three treatments from prestarter to finisher diets. In Trial Two the amino acid density decreased only in the four finisher diets. The main difference between predicted and actual results was the response to body weight. The model predicted a steady increase in feed intake to compensate for the lower dietary specifications while body weight did not change significantly. This increase in feed intake seems to be enough to maintain body weight. Trial birds also increased their feed intake as dietary amino acid density decreased, but this compensation seemed to be too low to maintain body weight compared to the control diet. The birds may find it easier to compensate when they have time to adapt to the specification. There is evidence in the literature that birds need seven days to adapt their feed intake to a lower feed specification (Leeson et al., 1996a). It can be speculated that the trial birds started to loose body weight due to a lower amino acid intake in this period. The model seems to adapt feed intake immediately after a change in diet specification. The simulation on literature data lead to the following conclusions: 1) Broilers posses the capacity to increase their feed intake with at least 65% should finisher diets with lower amino acid and energy concentrations be supplied. If only the energy concentration of finisher diets were decreased, the increase in feed intake will be around 30%. (see Table 16 and 23) 2) The accurate prediction of feed intake from the given dietary specification has a major influence on the accuracy of the prediction of broiler performance. 3) Amino acid density and DLys:ME ratio plays a significant role in the control and prediction of feed intake. The EFG broiler model is based on sound scientific principles. The model is comprehensive and can be used for a wide range of environmental and management conditions as well as dietary conditions. The nutritionist can use the model with confidence to assist in practical feed formulation. The actual strength of the model lies in the time and money being saved compared to practical trials. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie is om die prestasie en winsgewendheid van braaikuikens te bepaal wanneer voere met verskillende digthede tot op 35 dae gevoer word. Twee eksperimente is uitgevoer om produksieresultate te evalueer. Die resultate van hierdie eksperimente is met die voorspelde waardes uit die EFG simulasie-model vergelyk. Aangesien geen karkasdata vir bogenoemde eksperimente beskikbaar was nie, is twee gepubliseerde datastelle gebruik om hierdie deel van die model te evalueer (Leeson et al., 1996a). Twee braaikuiken eksperimente is uitgevoer. Eksperiment Een het uit drie behandelings bestaan waarvan die aminosuur-konsentrasie vanaf dag een tussen behandelings verskil het. In Eksperiment Twee het die aminosuur-konsentrasie net in die vier afrondingsdiëte verskil. Liggaamsmassa op 35 dae het die grooste verskil tussen voorspelde- en werklike waardes getoon. Beide voorspelde en werklike innames het in albei eksperimente verhoog soos wat aminosuur-konsentrasie afgeneem het. Voorspelde liggaamsmassa het egter konstant gebly terwyl werklike data 'n afname in liggaamsmassa getoon het. Dit bleik dat die voorspelde toename in innames voldoende was om massa te onderhou terwyl die voëls in werklikheid nie genoeg gekompenseer het nie. Leeson et al., 1996a het tot die gevolgtrekking gekom dat braaikuikens minstens sewe dae benodig om hul voeriname by 'n nuwe spesifikasie aan te pas. So 'n stadige aanpassing kan daartoe lei dat energie- en aminosuur-inname daal indien 'n dieet met laer spesifikasie gevoer. Dit sal daartoe lei dat die kuikens liggaamsmassa verloor. Uit die literatuur simulasies is die volgende afleidings gemaak: 1) Braaikuikens besit die vermoeë om voerinname in die afrondingstyd met minstens 65% te verhoog indien 'n afrondingvoer met laer amiosuur- asook energiekonsentrasie gevoer word. Indien net die energiekonsentrasie verlaag word, sal die inname met sowat 30% verhoog. 2) Die akkurate voorspelling van inname is krities vir die akkurate voorspelling van produksieparameters. 3) Aminosuur-digtheid en DLys:ME speel 'n belangrike rol in die beheer en voorspelling van voerinname by braaikuikens. Die EFG braaikuikenmodel is op suiwer wetenskaplike beginsels geskoei. Die model is omvattend en kan vir 'n wye reeks van omgewings- en bestuurstoestande asook dieet-spesifikasies gebruik word. Die voedingkundige kan die model met vertroue gebruik om met praktiese voerformulering by te staan. Die model kan die formuleerder baie tyd spaar aangesien praktiese eksperimente ingeperk kan word.

Evaluation of cowpeas (Vigna unguiculata l.) as a protein source for chicken egg production

Hlungwani, Caiphus. January 2011 (has links)
Thesis (MTech. degree in Agriculture.)--Tshwane University of Technology, 2011. / A ten week feeding trial was done with layer hens from 18 weeks of age to investigate whether cowpeas can be used as a single protein source for egg production.

Effect of Tenebrio molitor larvae as a protein source on growth performance, carcass yield and meat quality of broiler chickens

Mngqi, Sinethemba Census January 2015 (has links)
This study was conducted to assess the effect of including Tenebrio molitor larvae (T. molitor L) as a protein source in different diets on broiler performance, carcass characteristics and meat quality. A total of 144 day-old Cobb-500 chicks were randomly allocated into three treatment groups, each was allocated 16 birds and reared in 9 identical pens. Experimental diets used were as follows: T1 Control (no T. molitor L inclusion); T2 and T3 contained levels of T. molitor L at 5 percent and 10 percent of dry matter (DM) intake, respectively. Body weights (BW), average daily gain (ADG), feed intake (FI), and Feed conversion ratio (FCR) were measured for the 1st experimental chapter. For the second experimental chapter; live weights (LW) of broilers were recorded before slaughter and thereafter carcass weights (CW), meat yield (weights of breast, thigh, drumstick and wing) were recorded. The dressing percentage (DP percent) was also calculated. Breast muscles were sampled for meat pH and colour measurements. The LW of birds from T1 (0 percent T. molitor L) were significantly different (P<0.05) from both T2 (5 percent T. molitor L) and T3 (10 percent T. molitor L) which were similar to each other, with T2 exhibiting the highest live weights (2166g) and the control treatment exhibiting the lowest live weights (2018.3g). In CW, T1 was significantly different (P<0.05) from T2 while it was similar (P>0.05) to T3. The dressing percent of T1 was significantly different (P<0.05) from T2 and T3 which were similar to each other, with T2 having the highest dressing percentage (78, 2 percent) and T1 having the lowest DP percent (66 percent). The breasts in T2 were significantly higher and different (P<0.05) from both T1 and T3 which were similar to each other. The drumsticks in T3 were significantly different (P<0.05) from T1 while they were similar to T2 with values with T2 having highest values. After 45 minutes of slaughter, a significant difference (P<0.05) was observed in L⃰ among all treatments. In redness (a⃰), T3 was significantly different from T1 but was similar to T2 and all treatments in this study exhibited a darker red meat, with T3 muscles exhibiting darker red colour than the other treatments. Similar results were observed in yellowness (b⃰), where the breast muscles from T3 were more yellow than the other treatments. After 24 hours of slaughter, T2 L⃰ values were significantly different (P<0.05) from both T1 and T3 which were similar to each other. It was also found that the broiler chickens given diet with no T. molitor L inclusion (T1) had lower values of BW, FI, ADG and FCR throughout the experiment than those that were in T2 and T3 with 5 percent and 10 percent T. molitor L inclusion levels, respectively. However, it was also found that although broilers with 5 percent T. molitor L inclusion (T2) in their diet had high ABW and ADG than the broilers with 10 percent T. molitor L inclusion (T3), the T3 birds compared favourably to T2 birds as they required low feed intake to reach the same slaughter weight due to high FCR. It was, therefore, concluded that T. molitor L meal can be incorporated into the diets of broilers to produce heavy birds either at 5 or 10 percent. However, although 5 percent T. molitor L inclusion yields heavier carcasses, the 10 percent T. molitor L inclusion compared favourably to 5 percent inclusion since it required low feed intake to reach the same slaughter weights and there were slight differences on meat quality attributes between the two treatments.Thus T. molitor L at 10 percent inclusion levels was the best inclusion level to enhance broiler growth performance, carcass yield, meat yield and meat quality.

The effect of grain and soya bean-based diets on chicken production, some egg quality traits, and the potential for allergen carryover to eggs and meat

Dokora, Adia-En-Michelle January 2015 (has links)
This study determined the effect of maize-, whole wheat-, soya bean-based-diets on the growth performance, egg quality and dressing percentage of chickens, as well as the potential for soy and gluten allergen carryover to eggs and meat from chickens. Twenty 36-week-old Lorham White (LW) hens were divided into two groups and kept in individual cages until they reached 39-weeks of age, with water and feed supplied ad libitum. Ten LW hens were fed a maize/soya bean-based diet (T1) and the other ten birds were fed a maize/soya bean-based diet with a 15 percent whole wheat inclusion (T2) for a period of four weeks, with weekly individual hen weights and group feed consumption figures being recorded. After a two-week diet adaptation period, six eggs per treatment group were collected every second day from the LW hens’ to measure egg quality traits. Every third day, over a 29-day period, six eggs per treatment were collected and analysed for the presence of soy, gluten and gluten-derived peptides using allergen specific enzyme linked immunosorbent assays (ELISA) kits. For the broiler trial, a total of 160 Ross 308 mixed sex day old chicks were used in a completely randomized design. Two dietary treatments were assigned to eight cages (replicate) per treatment, with ten birds per cage. The Ross 308 broiler feeding programme consisted of three phases, starter (day 1 to day 10), grower (day 11 to day 20) and finisher (day 21 to day 28). At the beginning of the trial all chicks were fed T1 which contained a maize/soya bean-based diet for a period of 10 days and then eight cages with 10 birds per cage were randomly selected and fed the T2 diet, which contained a maize/soya bean-based diet with a 15 percent whole wheat inclusion, until they reached 28 days of age. Weekly live weights, feed intake, average daily gain and the average daily feed intake were recorded and calculated. At the end of the grower (day 21) and finisher phase (day 28), one broiler bird was selected per cage to have eight (8) birds per treatment and 16 birds per phase that were slaughtered and breast meat samples were analysed in duplicate for the presence of soy and gluten allergens using ELISA kits. The dressing percentage of hot carcasses was also determined at the end of the finisher phase on eight birds per treatment. For LW hens, live weight (LW) at 39 weeks of age, the average daily feed intake (ADFI) and weekly feed intakes (FI) were significantly different (P < 0.05) between treatments with birds on T2 recording higher gains. As birds age in weeks increased, significant differences (P < 0.05) in live weight values were recorded. Egg quality traits measured (shell weight, yolk weight, albumen weight, albumen height and Haugh units) were significantly different (P < 0.05) between treatments, with eggs from hens receiving T1 recording higher mean values. As hens got older, the colour of egg yolk improved, producing eggs with higher b* (yellowness) values and lower L* (lightness) and a* (redness) mean values. The Haugh unit, significantly improved (P < 0.05) as the hens got older, signifying better quality of eggs. For the broiler birds, growth traits measured indicated that there were no significant differences (P > 0.05) in live weight (LW), average daily feed intake (ADFI), weekly feed intake (FI), feed conversion ratio (FCR), cumulative feed intake (CFI) and cumulative gain (CG) between treatments. No significant differences (P > 0.05) between dressing percentage of broilers from the two treatments were observed. As birds grew, significant differences (P < 0.05) in LW, FI, AFI, FCR, and CFI, over a four-week period were recorded. Results of the allergen analyses indicated that soy and gluten allergens were not carried over from feed into eggs and meat of chickens fed a maize/soya bean-based diet and a maize/soya bean-based with a 15 percent whole wheat inclusion, respectively. In conclusion, a maize/soya bean-based diet and maize/soya bean-based diet with a 15 percent whole wheat inclusion that contained soy and gluten allergens, are feed sources that promote and stimulate 36-week-old LW hen and Ross 308 chicken growth.

Feed intake in chickens: genetic and social factors

Noble, Donald O. 29 September 2009 (has links)
The effects of genetic and social factors influencing ingestive behaviors, growth, livability, and dietary self-selection were investigated in three experiments. In Experiment I, ingestive behaviors, livability, and body weight were measured in lines of White Plymouth Rock chickens selected for high (HW) and low (LW) juvenile body weight reared in cages and floor pens as line-separate (S) and line-intermingled (I) flocks in three replicated trials. Body weights of Line HW chicks in cages, livability of Line LW chicks in cages, and ingestive behaviors of Line LW chicks in floor pens were higher in I than S flocks. Experiments II and III were designed to determine the ability of young chicks to discriminate among diets differing in amino acid content. In Experiment II, growth, feed intake, and feed preferences for diets varying in content of lysine, methionine, or tryptophan were measured in Line HW and a line of White Leghorns (HA) selected for high antibody response to sheep erythrocytes. Chicks were fed one of seven diets which were either balanced (Diet A), or slightly (1) or moderately (2) deficient in lysine (L), methionine (M), or tryptophan (T) for seven days. Chicks were then offered a choice between Diet A and the diet fed for seven days (3 to 10 days of age). Line HW chicks eventually showed a consistent preference for Diet A to all but Diet L1. For diet preference, interactions between time and diet were common in Line HW and the causes of these interactions were discussed. Line HA chicks preferred Diet A to M2, but otherwise did not choose between diets. Growth of Line HW chicks was reduced by feeding Diets L2, L1, and M2, but growth was not affected in Line HA. In Experiment III chicks from Lines HW, HA, and LW were provided a choice among diets with .85, .58, and .44 % methionine from one day of age. Line HW discriminated among diets with different methionine content from five days of age, but chicks did not make a consistent choice until after a period of deficiency. After a period of deficiency, Line HW chicks consistently chose the diet with .85 % methionine. Line HA chicks consumed more of the diet in slight excess of their methionine requirement and the reason for this is not clear. Line LW chicks did not discriminate among diets at any time during the trial. These results indicate that several factors interact to influence ingestive behaviors, growth, livability, and dietary self-selection in different genetic lines of chickens. / Master of Science

Genotype by feeding regimen interactions in growth selected chickens

O'Sullivan, Neil P. 24 January 2009 (has links)
Growth, reproduction, and immunocompetence were measured in lines of chickens maintained under different feeding regimens. Populations included a commercial broiler breeder parent line segregating at a sex-linked feathering locus (K, k⁺) and 4 experimental lines of which 2 had undergone 32 generations of divergent selection for 56-day body weight and 2 were their sublines in which selection has been relaxed for 5 generations. Mild feed restriction of the broiler line from 7 to 27 days of age reduced carcass fat and heterophil:lymphocyte ratios, and increased immune organ weight, antibody titer to sheep red blood cell (SRBC) antigen and livability than ad libitum fed birds. Body weights were similar by 56 days of age, and there was sexual dimorphism for rate of accelerated growth. Long term obesity, but not short term weight gain, was detrimental to reproductive performance, feed utilization, response to SRBC, and resistance to Escherichia coli, lymphoid leukosis and livability of broiler breeder dams. Poorer quality crumbles also reduced reproductive performance. An association between an endogenous viral gene encoding for avian leukosis virus (ev21) and the sex-linked K allele of the Z chromosome was confirmed in the broiler genome. Reproductive performance and feed utilization were inferior for K/- than k⁺/-, notwithstanding a pleiotropic effect of K associated with heavier egg and embryo weights. Variation in residual feed consumption was influenced by feathering genotypes and management practices. Increases in hatchability for the initial period after onset of lay were due to a reduction in early embryo deaths. Egg and 18-day embryo weights, ratios of embryo:egg and yolk:albumen, and proficiency of lipid transfer also increased but the latter was not associated with higher hatchability. Selection for 56-day body weight resulted in a divergence between lines at 21 days of age of 404% for body weight, 279% for feed intake and 138% for feed conversion ratio. Genotype by feeding regimen interactions were observed for growth and appetite development. Early posthatch growth of small intestine was highly correlated with subsequent growth of demand organs. Selection had also resulted in correlated changes in cell size of muscles, but not liver or small intestine which increased in size due to cell hyperplasia. Correlated changes in feed intake mediated synthesis and secretion of digestive enzymes. / Ph. D.

Effects of various male feeding regimens on reproduction in broiler breeders

Fontana, Eddy Alejandro 15 July 2010 (has links)
A study was conducted using commercial broiler breeders with the males fed a diet containing, either 120/0 or 140/0 protein and body weight maintained at either 900/0 or 1000/0 of that recommended by the primary breeder (fed separately), or allowed to eat from the female feeders (controls). Female feeders in the separately fed pens were equipped with especially designed grills, which denied access to the males. The male feeder in these pens was elevated so that females were denied access. Males fed separately (body weight 90% or 1000/0, and dietary protein 120/0 or 140/0) had a significantly higher percentage fertility (4.20/0) than males allowed to eat with the females. No differences in percentage fertility were found among the four separately fed groups. No differences were noted in percentage hatch of fertile eggs among any of the treatment groups. Males eating from the female feeders had significantly heavier body weights and testes weights at 65 weeks of age than breeder males in the separately fed, groups. Mean body weights were 3819g and 4773g at 35 weeks of age, and 4192g and 5443g at 65 weeks of age for males eating separately and eating with the females, respectively. Furthermore, males in the control group had significantly larger breast angle measurements when compared with the separately fed males. No differences were observed in foot scores and semen concentration among males in the various treatment groups. / Master of Science

Page generated in 0.0795 seconds