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
S. Javaid*, M. I. Anjum1 and M. Akram2
Livestock and Fisheries Research Unit, SARC, Pakistan Agricultural
Research Council, Karachi; 1Animal Sciences Institute,
National Agricultural Research Centre, PARC, Islamabad; 2Department
of Poultry Production, University of Veterinary and Animal Sciences,
Lahore, Pakistan
*Corresponding Author: shahbazparc@hotmail.com
Abstract
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.
Key words: Dietary protein and energy,
Meat, Molt layers, Proximate composition