Protein and lysine sources in nursery piglets diets

Abstract

Article 1, this experiment observed the effects of replacing animal and fish proteins with a fortified protein blend (PROPLEX MVP) on growth performance, immune status, microbial metabolites, and fecal scoring of nursery piglets. Dietary treatments were: 1) Control diet (CONT) with animal and fish protein sources; 2) PROPLEX MVP (MVP): CONT with MVP replacing Fish meal; 3) PROPLEX MVP 100 (MVP100): CONT with MVP replacing 100% of animal and fish proteins. For the overall nursery period, there were no significant differences in pig final BW, overall ADG and G:F. From the second week and during most of the experimental period, pigs fed CONT had greater (P < 0.05) fecal score, more soft and watery feces, and increased diarrhea incidence compared to MVP100 pigs. The total concentration of fecal volatile fatty acids was greater (P < 0.05) in CONT compared to MVP100 fed pigs. Plasma concentration of IgG, IgA, TNF-α, IL-4, and IL-6 did not differ significantly among dietary treatments. The use of MVP reduced (P < 0.05) by US$1.00 the total feed cost per pig and 10% to 12% of the feed cost per kg of live weight gain. Thus, the MVP protein blend can be used as cost effective alternative to animal and fish proteins in nursery pig diets. Article 2, the aim of this study was to evaluate the relative bioavailability (RBV) of L-Lys sulfate in comparison with L-Lys HCl and its effects on performance, blood parameters, intestinal functionality, and the apparent total tract digestibility in nursery piglets. The basal diet (CON) was lysine-deficient formulated to meet 73% of standardized ileal digestible Lys requirements. For the other diets, the CON was supplemented with three levels (80%, 90%, and 100% of Lys requirements) of L-Lys sulfate (70% L-Lys) or L-Lys HCl (79% L-Lys). There were no significant differences (P > 0.05) in the performance and concentrations of plasma urea between the L-Lys sources. The RBV of L-Lys sulfate relative to L-Lys HCl was 106%, 119% and 117% for effects on ADG, G:F and plasma urea, respectively. Lys deficiency resulted in a greater (P < 0.05) incidence of diarrhea, while pigs supplemented with Lys sulfate or Lys HCl showed greater (P < 0.05) villus height in the jejunum when compared to those receiving the CON. Diets supplemented with L-Lys sulfate had greater (P < 0.05) apparent total tract digestibility of dry matter, gross energy and crude protein. In conclusion, the RBV of L-Lys sulfate for effects on ADG, G:F and plasma urea is equivalent to that of L-Lys HCl for nursery piglets.