A Comparison of Six Protein Quality Assays Using Commercially Available Protein Meals , ,

Abstract

The protein quality of 20 commercially available animal by-product meals (9 meat and bone meals, 6 feather meals, 3 fish meals, and 2 hair meals) was evaluated using chick protein efficiency ratio (PER), net protein utilization (NPU), pepsin digestibility, Tetrahymena furgasoni bioassay, dye-binding, and chemical score. The first limiting amino acid(s) in the animal proteins for chick weight gain were the total sulfur amino acids (TSAA) for both meat and bone meal and fish meals; however, methionine was the first limiting amino acid for the keratin proteins, feather, and hair meals. Each protein quality test produced different rankings for the animal proteins; however, the correlation coefficients between PER and NPU, relative nutrient value (RNV), pepsin digestibility, dye-binding, and chemical score were r = . 922, .856, .910, .628, and .883, respective-ly, for the 20 animal proteins. The pepsin digestibility values correlated the highest with the chick growth assays, (PER and (NPU) suggesting the pepsin test may be a quick reliable method to evaluate protein quality in animal by-products.

Standardized ileal amino acid digestibility in dry-extruded expelled soybean meal, extruded canola seed-pea, feather meal, and poultry by-product meal for broiler chickens

“…The CV for AA ranged from 1.2% (Val) to 2.0% (His, Phe, and Cys) and 1.1% (Thr) to 5.0% (Met and Cys) for DES-BM and ECSP, respectively. The CP and AA composition of PBPM and FM samples compared well with previously published values (Daghir, 1975;Johnston and Coon, 1979;Baker et al, 1981;Papadopoulos et al, 1986;Wang and Parsons, 1998;Ravindran et al, 2005). The AA profile of PBPM and FM showed a somewhat similar trend, with Met and His ranking the lowest.…”

Digestibilities of nitrogen and amino acids in soya-bean, sunflower, meat and rapeseed meals measured with pigs and poultry

“…Also, the pepsin test detected the lower digestibility of nitrogen in meat meal 1 compared with meat meal 2, although the sensitivity of the pepsin test would seem to be less than that of the in vivo assays. Johnston and Coon (1979a) found that the pepsin test correlated well with protein efficiency ratio measured with chicks, for a range of animal by-product meals. These workers used a more dilute solution of pepsin (0-002% (weight/volume)) than that used in this trial (0-2% weight/volume), so their test was likely to have been of greater sensitivity (Johnston and Coon, 1979b).…”

In‐vitro determination of nitrogen digestibility and lysine availability in meat and bone meals and comparison with in‐vivo ileal digestibility estimates

“…As an alternative, several in-vitro digestibility assays have been developed, some of which have shown considerable promise (Satterlee et ul 1981). Earlier Rayner and Fox 1978; Johnston and Coon 1979) relied upon single enzyme digests. However, multi-enzyme assays more closely simulating conditions found in the live animal have been developed, and high correlations with in-vivo digestibility data have been reported (Akeson and Stahmann 1964; Saunders and Kohler 1972; Saunders t't crl 1973; Hsu et a1 1977;Buchmann 1979; Clunies and Leeson 1984).…”