Effects of Feeding Different Protein Supplements on Digestibility, Nitrogen Balance and Calcium and Phosphorus Utilization in Sheep

Two metabolism trials were conducted with 24 wether lambs to investigate the effects of feeding crab meal and other protein supplements on N utilization, digestibility and Ca and P balance in sheep. The lambs (avg. BW, 25 kg) were randomly allotted to eight diets in each of two trials. The supplements were: i) none, negative control (NC); ii) soybean meal (SBM), control; iii) supplement based on industrial byproducts of both plant and animal origin (IPA); iv) experimental supplement based on byproducts of animal origin (ESA); v) hydrolyzed supplement No 4. (HESA); vi) commercial supplement based on animal protein (CS), $Pro-Lak^{(R)}$ vii) crab meal (CM); and viii) urea (U). The supplements supplied 33% of the total dietary N (CP, 9.8%; DM basis). Lambs fed the NC diet had lower (p<0.05) DM and OM digestibility. Lower (p<0.05) apparent absorption of N was recorded for the lambs fed the HESA and NC diets. Sheep fed CM had lower Ca absorption compared to SBM. Highest (p<0.05) P absorption was observed for lambs fed CS and CM and lowest for U and NC diets. Sheep fed CM had higher (p<0.05) total VFA concentration (65.7 ${\mu}mol/ml$), compared to those fed ESA, CS, and NC diets (47.3, 49.8, and 49.5 ${\mu}mol/ml$, respectively). Highest (p<0.05) ruminal $NH_3$ N (29.6 mg/dl) was observed in lambs fed the U diet, while those fed the NC diet had the lowest (p<0.05) average value (7.66 mg/dl). Lambs fed the U diet had the highest (p<0.05) blood urea N (10.67 mg/dl). The present study showed that N utilization of diets supplemented with experimental supplements based on feather meal and blood meal; commercial supplement based on animal protein, $Prolak^{(R)}$ supplement based on plant protein and blood meal; and crab meal are comparable with that of soybean meal.