Whey, which is a co-product from dairy processing plants that extract fat and protein from milk to make cheese has been used in diets fed to weanling pigs as a source of lactose. Whey powder does not contain much protein because the majority of the milk protein ends up in the cheese during processing. However, cheese co-products, which contain 40 to 50% crude protein may be used in the feeding of pigs but there is limited information about the nutritional value of cheese co-products fed to pigs. Therefore, it was the objective of this experiment to measure the apparent ileal digestibility (AID) and the standardized ileal digestibility (SID) of amino acids (AA) by weanling pigs in a cheese co-product and compare values to those obtained in fish meal and in a source of enzyme treated soybean meal (HP 300).
Animals, Housing, Experimental design, and diets
Eight weanling barrows with an average initial BW of 11.0 ± 0.4 kg that had a T-cannula installed in the distal ileum were allotted to a replicated 4 × 4 Latin square design with 4 diets and four 7 d periods in each square. There was 2 pigs per diet in each period for a total of 8 observations per treatment. Pigs were placed in individual pens (1.2 × 1.5 m) that were equipped with a self-feeder, a nipple waterer, and a slatted tri-bar floor. Three diets were based on HP 300, fish meal, or the cheese co-product Pro88 provided by Keys Manufacturing Inc., as the only AA-containing ingredients. An N-free diet was included in the experiment to measure basal endogenous losses of crude protein and AA. Thus, a total of 4 diets were used. Vitamins and minerals were included in all diets to meet or exceed the estimated nutrient requirements for weanling pigs. All diets also contained 0.40% chromic oxide as an indigestible marker. The first 5 d of each period was considered the adaptation period to the diet, whereas ileal digesta were collected for 8 h on d 6 and 7 of each period. Data for AID and SID of CP and AA were analyzed using a model that included diet as fixed effect and pig and period as random effects.
Results
The analyzed crude protein and AA composition of HP 300 was 56.07 % CP and 3.07% Lys, fish meal was 64.99 % CP and 4.84 % Lys, and Pro88 was 43.65 % CP and 2.98 % Lys.
No difference was observed between HP 300 and fish meal for AID of crude protein and most AA, but Pro88 was greater (P < 0.05) for AID of crude protein and most AA compared with HP 300 or fish meal (Table 1). Likewise, the SID of crude protein and most AA was not different between HP 300 and fish meal, but these protein sources had lower SID of crude protein and most AA ( P < 0.05) compared with Pro88 (Table 2).
Key points
- The cheese co-product used in this experiment had a greater digestibility of amino acids than fish meal and enzyme treated soybean meal.
- Pro88 is highly digestible in terms of amino acids when fed to weanling pigs.
Table 1. Apparent ileal digestibility (AID) of crude protein and amino acids in enzyme treated soybean meal (HP 300), fish meal, and cheese co-product1
a-bLeast squares within a row lacking a common superscript letter are different (P < 0.05).
1Each least squares mean represents 8 observations per diet, except cheese co-product diet that mean represents 7 observations.
Table 2. Standardized ileal digestibility (SID) of crude protein and amino acids in enzyme treated soybean meal (HP 300), fish meal, and cheese co-product1,2
a-bLeast squares within a row lacking a common superscript letter are different (P < 0.05).
1Each least squares mean represents 8 observations per diet, except cheese co-product diet that mean represents 7 observations.
2Values for SID were calculated by correcting the values for apparent ileal digestibility for basal ileal endogenous losses. Basal ileal endogenous losses were determined (g/kg of dry matter intake) as crude protein, 18.80; Arg, 0.58; His, 0.27; Ile, 0.50; Leu, 0.79; Lys, 0.56; Met, 0.13; Phe, 0.50; Thr, 0.88; Trp, 0.17; Val, 0.68; Ala, 0.69; Asp, 1.13; Cys, 0.34; Glu, 1.29; Gly, 1.45; Pro, 2.34; Ser, 0.72; and Tyr, 0.40.