Animal wastes. I. Effect of processing on the chemical and protein nutritional value of calf stomach.
The nutritive value of calf stomach waste from rennet production was assessed. The by-product was either drum-dried at the industry (DDSW) or mildly dried (60 degrees C) in a ventilated oven at the laboratory (MDSW). Part of the sample treated at the laboratory was autoclaved before drying (ASW). The protein and ether extract concentrations ranged from 34.25% to 44.31% and from 31.14% to 38.95%, respectively, and were lower in DDSW than in the other two samples. The ash content which ranged from 16.04% to 27.38%, was higher in the DDSW sample. Methionine, cystine, and available lysine were lower in the DDSW by-product than in the other two samples. Lysine availability was affected by the drum-drying and autoclaving procedures. Tryptophan was shown to be the limiting amino acid in all samples. Nutritive value, assayed both in DDSW and ASW, was lower in DDSW when compared with ASW or with casein diets as far as PER is concerned. The digestibility was shown to be ranked in increasing order for DDSW, ASW and casein. In conclusion, the results indicate that the waste from rennet production may be recommended as in inexpensive source of protein for animal feeding.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001835:Body Weight; D002417:Cattle; D004044:Dietary Proteins; D008297:Male; D009753:Nutritive Value; D051381:Rats; D011919:Rats, Inbred Strains; D013270:Stomach; D014866:Waste Products / Q000032:analysis*
D000596:Amino Acids; D004044:Dietary Proteins; D014866:Waste Products