Browsing by Author "Fontana, Eddy Alejandro"

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    The effect of early feed restriction on the performance, organ weights, carcass composition, and lipid and protein metabolism in broiler chickens
    Fontana, Eddy Alejandro (Virginia Tech, 1991-05-05)
    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.
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    Effects of various male feeding regimens on reproduction in broiler breeders
    Fontana, Eddy Alejandro (Virginia Tech, 1988-07-15)
    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.