Effect of Dietary Fish Peptide and Enzyme Supplementation on Weanling Pigs

Abstract

A corn-soy diet is the gold standard for feeding pigs, however, such a diet may not be appropriate for weanling pigs. Weanling pigs are subjected to various stressors at weaning, and their digestive system is immature or the secretion of digestive enzymes is not sufficient to utilize corn-soybean meal (SBM) diets. For that reason, traditionally, weanling pigs have been provided with complex diets containing many special ingredients such as dried whey, plasma protein, fishmeal, soy protein concentrate, and others. Feeding such diets with highly palatable and digestible feed ingredients is very effective in promoting the growth performance of weanling pigs, however, using such diets can be rather costly. With the development of, e.g., fish peptides, which can be not only a great source of nutrients and but also considered as a bioactive or functional feed additive, and multienzyme complexes it might be possible to use corn-SBM diets more successfully for weanling pigs. A total of 48 pigs (24 females and 24 castrated males) weaned at 3 to 4 wk of age (initial body weight, 7.77 ± 0.78 kg) were used to investigate the possibility of replacing a complex diet with a simple corn-soybean meal (SBM) diet by fish peptide and multienzyme complex supplementation. Pigs were randomly assigned to 3 dietary treatments with 4 replicate pens per treatment and 2 gilts and 2 castrated males per pen. A two-phase feeding program (2 wk each) was used, and 2 typical complexes, positive control (POS) diets were formulated to contain 12.15 and 11.07 g standard ileal digestible Lys/kg for Phase 1 and 2, respectively. In addition to corn and SBM, the complex diet for Phase 1 contained dried whey, fishmeal, plasma protein, poultry fat, and Zn oxide, whereas the complex diet for Phase 2 contained dried whey and fishmeal. Two simple, corn-SBM negative control (NEG) diets were formulated to be isolysinic to the POS diets for Phase 1 and 2 and included 1.5% fish peptides. The NEG diets were supplemented with multienzyme complexes. During the fourth week of the study, a blood sample was collected from each pig, and samples were analyzed for serum metabolites. Pigs were allowed ad libitum access to feed and water throughout the 4-wk study period, and the pig weight and feed consumption data were collected weekly. During the second week of the study (d 7 to 14), weight gain (WG) of pigs fed the POS diet was numerically lower (P = 0.144) than those fed the other 2 diets, which was reflected in the efficiency of feed utilization for WG. Pigs fed the NEG and ALL diets had greater gain to feed (G:F; P = 0.034), gain to Lys (G:Lys) intake (P = 0.034), and gain to DE (G:DE) intake (P = 0.013) than those fed the POS diet. Furthermore, G:F (P = 0.037), G:Lys intake (P = 0.037), and G:DE intake (P = 0.010) were greater in pigs fed the ALL diet than those fed the NEG diet. As in d 7 to 14, pigs fed the NEG and ALL diet had numerally greater weight gain than those fed the POS diets (P = 0.147) during the first 2 wk of the study, which was reflected in the efficiency of WG. During Phase 1 (d 0 to 14), the efficiency of feed (P = 0.004), Lys (P = 0.004), or DE (P < 0.001) utilization was greater in pigs fed the NEG and ALL diets than those fed the POS diet. In addition, pigs fed the ALL diet tended to have greater G:F (P = 0.095) and G:Lys intake (P = 0.095) and had greater G:DE intake (P = 0.009) than those fed the NEG diet. There seemed to be no clear effect of dietary treatments on overall growth performance (d 0 to 28) of weanling pigs or serum metabolite profile during the last week of the study. During the first 2 wk of the study, fish peptides improved growth the performance of weanling pigs, and additional supplementation with multienzyme complexes improved growth performance further. The results indicated that it may be possible to replace a complex diet with a simple corn-SBM diet by supplementing the weanling pig diet with fish peptides and multienzyme complexes during Phase 1 (d 0 to 14).