Effect of dietary protein and energy level on proximate composition of breast and thigh meat in White Leghorn layers at molt and post molt production stages.

摘要

An experiment was conducted to explore the effects of varying protein and energy levels in molt diets on meat composition of White Leghorn layers. One hundred and fifty four, 70 weeks old, layers were randomly divided into 18 experimental units of 8 hens each in addition to 10 birds that were slaughtered at pre molt and post fast stages. After 10 days of fasting during molting, 6 experimental diets having 3 levels of crude protein (CP) i.e. 14, 16 and 18% and 2 levels of metabolizable energy (ME) i.e. 2700 and 2900 kcal/kg were given to the birds at the rate of 45 g/bird for 25 day. There after the birds were offered ad-libitum layer ration during production phase. Two birds per replicate at post molt, at 50% egg production and at the end of experiment were slaughtered and then breast and thigh meat samples were analyzed for proximate composition. Moisture (71.7 and 70.0%) content was significantly (P<0.05) higher while, ether extract (2.13 and 3.49%) was significantly (P<0.05) lower in both breast and thigh meat, respectively, with 18% CP diet as compared to 14 and 16% CP diets. Medium Protein-High Energy (MPHE) molt diet having 16% CP with 2900 kcal/kg ME produced more dry matter and protein content in meat at the expense of ether extract. Results regarding proximate composition of layer meat determined at different stages of molting and post molt production revealed that moisture and protein contents of both breast and thigh meat were significantly increased where as, ether extract and ash contents were significantly decreased at post fast stage with respect to other stages.