Chickens from lines selectively bred for high and low antibody response to sheep red blood cell antigen and reciprocal crosses between them were fed diets containing 0, 1, 2, 3, and 6 micrograms of total aflatoxin/g diet from 2 to 42 days of age. Low-line birds, although larger, did not differ from the high-line birds in feed consumption, feed conversion, surface, or cloacal temperatures. Differences between crosses and parental lines varied according to the particular trait. Responses to dietary aflatoxin were similar regardless of population. Aflatoxin depressed body weight, feed consumption, and feed conversion at 14 days and subsequent ages with the effect on body weight and feed consumption occurring at lower levels than that noted for feed conversion. Although aflatoxin did not alter cloacal temperatures, there were progressive decreases in surface temperatures at 2 micrograms/g and higher.
A phenotypic profile was compiled for eight commercial broiler stocks fed diets containing two levels of methionine and lysine. Stock by diet interactions were unimportant for most traits, although differences among stocks were somewhat magnified when they were fed the lower levels of methionine and lysine. Feed efficiency (body weight/feed consumption) to a fixed age was negatively associated with body weight, feed intake, frequency of leg disorders, and size of the abdominal fat pad. Its association with immunological and physiological traits varied with the environment. Apparent improvements in performance may be partially attributed to increases in growth rate, which have enabled broilers to reach market age at earlier ages.
Four dietary treatments differing in protein levels were compared to ascertain the protein requirement of laying Japanese quail in a semi-arid environment. One hundred and twenty quails were randomly assigned to four treatments (TI — 22%CR T2 — 20%CP T3 — 18%CP and T4 - I6%CP) in a completely randomized block design Each treatment was replicated thrice with ten quails each. Feed intake, body weight gain, hen day egg production, feed conversion ratio FCR), egg quality and hematological constituents were the response criteria. The study lasted seven weeks. Feed and water were provided ad libitum throughout the experimental period No significant (P> 0.05) effect of dietary protein was observed for feed intake, average body weight gain, hen-day egg production, F CR, dressing percentage and hematological parameters. Average body weight was significantly (P<0,05) enhanced by high dietary protein. Egg weight and Haugh unit were significantly (P<0. 05) better for the groups fed the higher protein levels (20 and 22% CP). Hen-day egg production, albumen index, specific gravity, shell weight and percent shell were not affected (P>0.05) by dietary protein levels. The costs of producing l kg egg in the treatment groups were ₦25926, ₦21007, ₦252.44 and ₦1263./10 for T1, T2, T3 and T4, respectively. It was concluded that about 20%CP is required in the diets of laying Japanese quail under a semi-arid environment of Nigeria.
Aflatoxin was fed to chickens from lines selected for high and low antibody response to sheep erythrocyte (SRBC) antigen and reciprocal crosses between the two lines. Differences were found among populations for liver, bursa, and thymus weight and antibody production to SRBC but not for spleen weight or heterophil: lymphocyte ratios. Dietary aflatoxin depressed absolute and relative weights of bursae and thymi and absolute weights of livers and spleens. Relative to body weight, however, liver and spleen weights increased. There was a large decrease in liver metabolism and a dramatic increase in heterophil: lymphocyte ratios when 5700 ppb of aflatoxin was fed, but no alteration in antibody production to SRBC antigen was detected. Population by response to aflatoxin interactions were not significant for any of the traits measured except bursa and spleen weights, suggesting a general response to this mycotoxin among lines of chickens known to be immunologically different.
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