This study was conducted to determine the effect of egg weight on hatchability and chick hatch-weight of Cobb 500 broiler chickens. A total of 396 Cobb 500 hatchable eggs classified according to three different egg weight groups as small: (<49 g) medium: (50-59 g) and large: (60-69 g) were used in the experiment. A complete randomized design of three treatments with three replicates and each replicate having” 44 eggs was used for the experiment. Simultaneously a linear type equation was used to determine the relationship between egg size and responses in hatchability values and chick hatch-weight. Results indicated that large-sized eggs produced chicks with higher (P<0.05) hatch-weight than medium and small-sized eggs. However, no differences were detected with fertility rate percentage, hatchability percentage and percentage hatch of fertile. It was therefore concluded from the result of the present study that sorting of Cobb 500 broiler chicken breeder eggs by weight prior to incubation might be advantageous in producing uniform size Cobb 500 broiler chicken hatchlings to meet specific market demands with improved efficiency. / Agriculture and  Animal Health / M. Sc. (Agriculture)

This study was conducted to determine the effect of egg weight on hatchability and chick hatch-weight of Cobb 500 broiler chickens. A total of 396 Cobb 500 hatchable eggs classified according to three different egg weight groups as small: (<49 g) medium: (50-59 g) and large: (60-69 g) were used in the experiment. A complete randomized design of three treatments with three replicates and each replicate having” 44 eggs was used for the experiment. Simultaneously a linear type equation was used to determine the relationship between egg size and responses in hatchability values and chick hatch-weight. Results indicated that large-sized eggs produced chicks with higher (P<0.05) hatch-weight than medium and small-sized eggs. However, no differences were detected with fertility rate percentage, hatchability percentage and percentage hatch of fertile. It was therefore concluded from the result of the present study that sorting of Cobb 500 broiler chicken breeder eggs by weight prior to incubation might be advantageous in producing uniform size Cobb 500 broiler chicken hatchlings to meet specific market demands with improved efficiency. / Agriculture and  Animal Health / M. Sc. (Agriculture)

A procedure was developed to examine factors contributing to skin strength of meat-type chickens. Skin breaking strength was initially measured in lines of chickens divergently selected for high (H) and low (L) juvenile body weight, their reciprocal crosses (HL and LH), and an F₂ generation derived from HL and LH matings. Skin of chicks from the LL line was weakest, that from the HH and LH matings strongest, and that from HL and F₂ matings was intermediate. Percentage heterosis for breaking strength was significantly positive while percentage recombination was not significant. Skin breaking strength and protein, fat, moisture, and total collagen concentrations of skin from the breast, thigh, and back of male and female commercial broilers were then examined in response to diets containing relatively wide or narrow ratios of calories to protein (C:P). Comparisons were made at 28, 42, and 56 days of age. Chickens fed diets containing wider C:P ratios had weaker skin than those fed diets with narrower C:P ratios, with the differences being greater at older than at younger ages. Males had stronger skin than females. Among body sites, breast skin was stronger than thigh skin with that from the back being intermediate in strength. Skin breaking strength did not appear to be consistently associated with either the protein, fat, or collagen concentrations in the skin. Skin from broiler chicks fed diets with differing C:P ratios was also examined histologically. Males had stronger and thinner skin than females, with the differences in thickness due primarily to differences in the thickness of the hypodermis. Regardless of sex, feeding diets containing wider C:P ratios resulted in weaker and thicker skin. The thicker skin was associated with an increase in the thickness of the hypodermis and a decrease in the thickness of the dermis and epidermis. With the exception of differences between back and thigh skin, increases in breaking strength occurring between skin from different sites were associated with a reduction in total skin thickness and in the thickness of the hypodermis. It was concluded that increased hypodermis thickness and/or decreased thickness of the dermis and epidermis reduced skin strength. Two experiments were conducted in which skin strength was examined in relation to heat stress and supplemental ascorbic acid. In the first experiment, chicks fed diets containing 0 or 100 mg of ascorbic acid per kg of diet were subjected to either a constant ambient temperature of 23C, a constant ambient temperature of 32C, or a treatment consisting of 32C from 1600 to 1200 hr and 400 from 1200 to 1600 hr (32/400). Both heat stress and supplemental ascorbic acid tended to increase collagen concentrations in the skin, but differences in breaking strength were inconsistent in response to these treatments. Supplemental ascorbic acid, however, partially alleviated reductions in body weight due to heat stress but did not decrease body temperatures of heat-stressed chicks. In the final experiment, diets containing either 0, 200, or 400 mg/kg of supplemental ascorbic acid were fed to chicks maintained at ambient temperatures of 23 and 34C. Contrary to previous observations, ascorbic acid failed to ameliorate the depressive effect of heat stress on body weight. Supplemental ascorbic acid tended to reduce adrenal, bursa of Fabricius, and spleen weights but had no effect on heterophil and lymphocyte numbers or ratios. Adrenal ascorbic acid concentrations were not significantly affected by supplemental ascorbic acid and plasma ascorbic acid levels were inconsistent among treatment groups. Neither supplemental ascorbic acid nor heat stress significantly influenced skin strength. It was concluded that supplemental ascorbic acid was not beneficial in improving skin strength in commercial broiler chicks. / Ph. D.

LD2668 .T4 1954 S57 / Master of Science

Call number: LD2668 .T4 1950 W55 / Master of Science

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.

Made available in DSpace on 2014-06-11T19:30:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-05-11Bitstream added on 2014-06-13T19:18:48Z : No. of bitstreams: 1 fernandes_bcs_me_botfmvz.pdf: 296743 bytes, checksum: 816b2969cb20cde8f115860eef8546af (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Universidade Estadual Paulista (UNESP) / Com objetivo de avaliar a integridade intestinal, por meio da microscopia óptica e eletrônica de varredura (MEV), e o desempenho de frangos de corte suplementados com aditivos alternativos aos antimicrobianos foram alojados 1080 pintos machos, com densidade populacional de 12 aves/m². O delineamento experimental foi o inteiramente casualizado, com seis tratamentos e seis repetições de 30 aves cada. Os tratamentos foram: dieta basal (controle); dieta basal mais antimicrobiano; dieta basal mais probiótico; dieta basal mais prebiótico; dieta basal mais simbiótico e dieta basal mais ácidos orgânicos. Foram avaliados o ganho de peso, consumo de ração, conversão alimentar e viabilidade aos 10, 21, 35 e 42 dias de idade. Aos 42 dias, 72 aves (duas aves por repetição de cada tratamento) foram pesadas individualmente e eutanasiadas. Para avaliação da morfometria das diferentes túnicas da parede intestinal foram coletados segmentos do intestino delgado e cecos de duas aves por repetição e para as análises da integridade intestinal (MEV) foram coletados os mesmos segmentos de duas aves por tratamento. No período inicial de criação as aves suplementadas com os aditivos alternativos mostraram ganho de peso similar àquelas tratadas com antimicrobiano, porém não diferiram do grupo controle. A conversão alimentar das aves que receberam aditivos alternativos no intervalo de 1 a 10 dias foi melhor que o controle, porém para os demais períodos de criação a conversão alimentar foi similar ao antimicrobiano sem, contudo diferir do controle. A morfometria das diferentes túnicas da parede intestinal das aves não foi influenciada pelos tratamentos. No período total de criação, os aditivos alternativos avaliados não melhoraram a integridade intestinal, bem como o desempenho dos frangos de corte / In order to evaluate the intestinal integrity, through optical microscopy and scanning electronic (SE), and the performance of broilers receiving diets supplemented with additives instead of antimicrobial growth promoters 1080 male chicks were allocated in a population density of 12 birds / m2. The experimental design was a completely randomized arrangement with six treatments and six replications of thirty birds each. The treatments were: basal diet (control); basal diet + antimicrobial growth promoter (AGP); basal diet + probiotic; basal diet + prebiotic; basal diet + symbiotic; and basal diet + organic acids. The weight gain, feed intake, feed:gain ratio and the viability at days 10, 21, 35 and 42 were evaluated. At 42th day, 72 birds (two birds per replicate of each treatment) were individually weighted and sacrificed. For morphometric evaluation of different tunics of intestinal wall, small intestine and caecum fragments from 2 birds per repetition were collected and for intestinal integrity analysis (SE) the same fragments were collected from 2 birds per treatment. At the first period of breeding alternative additives-fed chickens showed similar weight gain compared to AGP-fed chickens, but they did not differ from control group. The feed:gain of alternative additives-fed chickens from 1st to 10th days was better than control group, but for the others periods the feed:gain ratio was similar to AGP-fed birds, without differing from control group. The morphometric of different tunics of intestinal wall was not influenced by treatments. The alternative additives did not improve the intestinal integrity, neither the broiler performance during the whole breeding period

Studies were conducted to investigate the fermentation and nutritive value of ensiled broiler litter and corn forage. The non-processed broiler litter, containing a wood shaving base, contained 82.9% DM, 26.8% crude protein, 23.0% crude fiber and 16.7% ash. Corn forage was harvested at two stages of maturity, corresponding to 26 and 38% DM. Two studies, one designated "small-bag" and one designated "large-bag" were conducted. For the small-bag study the treatments at each maturity were: untreated; urea, 0.5%, wet basis; and litter at levels estimated to contribute 15, 30 and 45% of the total dry matter. For these, mixtures were mixed by hand in 2 kg amounts and packed into small polyethylene bags supported in cardboard food containers. For the large-bag study the treatments at reach maturity were: untreated; urea, 0.5%, wet basis; and levels of litter to contribute 15 and 30% of the total dry matter. The large-bag silages were mixed with shovels and ensiled in large polyethylene bags containing approximately 114 kg per bag. Both the small-bag and the large-bag silages were evaluated on the basis of nutrient composition and characteristics of fermentations such as pH and organic acid concentration. Total bacteria and coliform counts were conducted on the small-bag silages to evaluate fermentation as a means of destroying microorganisms present in litter. The large-bag silages were fed to sheep in two metabolism trials and two palatability trials to study the digestibility, nitrogen utilization and voluntary intake of the ensiled mixtures. The addition of broiler litter resulted in significant increases (P < .01) in dry matter, crude protein and ash for silages made from forage harvested at both maturities. Litter increased the crude protein from about 8% (dry basis) for the control treatment to about 11, 15 and 18%, respectively, for silages in which litter contributed 15, 30 and 45% of the total dry matter. Ammonia concentrations of silage were increased (P < .01) by each level of litter. Litter and urea appeared to buffer the organic acids of fermentation resulting in final concentrations of lactic acid that were higher than control silages. Total bacteria numbers were in excess of 3 million per gram; however, only the highest level of litter in maturity 2 silages and the two highest levels of litter in maturity 2 silages had significantly higher counts than controls. Coliforms were no higher in litter silages than controls. When fed to sheep, dry matter digestibility was similar for all silages. Crude protein digestibility was depressed by advancing maturity of the corn plant, but significantly increased by each level of litter. Nitrogen retention data indicated that litter nitrogen was well utilized; however, increasing the level of litter from 15 to 30% of the dry matter depressed efficiency of dietary nitrogen utilization. Dry matter intake was significantly greater (P < .01) for silages containing litter than for control and urea silages. There were no significant differences in dry matter intake associated with forage maturity. / Ph. D.

Five experiments were conducted to investigate the effects of early feed restriction on body weights, feed conversion, organ weights, fat deposition, carcass and muscle composition, plasma lipids, lipogenesis, lipolysis, and muscle tissue DNA and RNA in broiler chickens. In Experiments 1 and 2, broiler chicks were reared in litter pens for 49 days, while Experiments 3,4, and 5 were conducted in battery cages for 28 days. Feed restriction in all experiments was induced by providing male broiler chicks with 40 kcal/bird/day for 7 (Experiments 1 and 2) or 6 (Experiments 3, 4, and 5) days, starting at 4 days of age. Feed restriction (40 kcal/bird/day) for broiler females in Experiment 1 was imposed from 4 to 9 days of age. Ad libitum feeding was resumed after the restriction periods and continued to the conclusion of each experiment. Broilers fed ad libitum for the entire experimental period were used as controls in each study. Broilers under early feed restriction had significantly (P s .05) lower mean body weights than ad libitum fed controls, for all ages measured. However, feed to gain ratios for restricted birds were Significantly lower at 28 (Experiments 1 through 4) and 49 (Experiments 1 and 2) days of age than for birds fed ad libitum. Total pen body weights for restricted and ad libitum fed groups were similar at 49 days of age in Experiments 1 and 2 which, reflected a significant reduction in the rate of mortality observed in the early restricted groups. Significantly higher levels of lipogenic activity, plasma triglycerides and lipoproteins (VLDL + LDL), and significantly larger abdominal fat pads were observed in restricted broilers than in ad libitum fed controls at 28 days of age (Experiment 4). No significant differences were found in organ weights, carcass composition, lipolysis, and muscle tissue DNA/RNA levels, and muscle composition between early restricted and unrestricted broilers. Results from these studies indicate that restricted broilers were not able to attain body weights comparable to ad libitum fed birds at 49 days of age. In contrast, early feed restriction resulted in consistently better feed efficiency in restricted birds when compared to controls. Furthermore, it appears that early feed restriction altered lipid metabolism early in life; however, organ weights, fat deposition, muscle composition, and carcass composition were only minimally affected by this procedure. / Ph. D.

Two experiments were conducted to evaluate the effects of arginine, vitamin E, and their combination on cardiopulmonary performance and nitric oxide synthase (NOS) activity in broilers undergoing cold-induced ascites (pulmonary hypertension) after an acute challenge with epinephrine. One day-old male broilers ( n = 25/treatment) were supplemented with arginine (0.3% water supplementation), vitamin E (400 IU/L or kg, water or feed supplementation; experiment 1 and 2 respectively) or both compounds, above NRC (1994) recommendations. From day 28 to 42, a catheterization was performed (n = 8/treatment) to evaluate pulmonary and mean arterial pressures, and heart rate. After recording baseline values, two injections of epinephrine (1 or 0.5 mg/kg body weight, experiment 1 and 2, respectively) were administered in a 20 min interval. The NOS activity was estimated through the conversion of 14C-arginine to 14C-citrulline in isolated pulmonary arteries ( n = 8/treatment). Overall, the time taken for pulmonary arterial pressure to return to values no different from initial baseline levels was longer for the birds consuming high levels of vitamin E (alone or in combination with arginine) compared to birds supplemented only with arginine. Although NOS activity was highly variable, birds fed with high arginine levels tended to have the lowest NOS activity. These results showed that vitamin E supplementation at the levels used in these experiments has detrimental effects on cardiopulmonary performance, and does not improve NOS activity in isolated pulmonary arteries.