Impact of feeding fermentable proteins and carbohydrates on growth performance, gut health and gastrointestinal function of newly weaned pigs

Abstract

Feeding fermentable carbohydrates (FC) to weanling pigs may reduce the negative impact of proteolytic fermentation on gastrointestinal health and function. A total of 144 newly weaned pigs [6.23 kg body weight (BW); six pens per treatment; six pigs per pen) were used to determine the interactive effects of feeding additional fermentable protein (FP) and FC on growth performance, gastrointestinal function and intestinal health. Dietary treatments, based on a 2 × 2 factorial arrangement, were: (1) basal diet (control); (2) control + 10% poultry meal (PM) as FP source; (3) control + 5% beet pulp (BP) as FC source; and (4) control + 10% PM and 5% BP. Diets were formulated to be similar in digestible energy (DE) and digestible amino acid contents. In general, no interactive effects of FC and FP were observed (P > 0.10). During the 3-wk post-weaning period, feeding FP reduced average daily gain (ADG) (242 vs. 269 g d-1; P < 0.05), while FC increased ADG (269 vs. 243 g d-1; P < 0.05). Overall, feed intake did not differ between treatments (P > 0.10). On days 14 and 28 post-weaning, Clostridia spp. counts in colon contents, counts of white cells and segmented neutrophils in blood were lowered (P < 0.05) by feeding FC. Blood urea nitrogen was increased by feeding FP (9.5 vs. 6.5 mg dL-1; P < 0.05), while ammonia concentration in colon contents was lowered by FC (154 vs. 193 µg mL-1) (P = 0.06). Among biogenic amines, levels of tyramine (140 vs. 304 nmol g-1 DM) and spermidine (174 vs. 219 nmol g-1 DM) in colon contents were lowered (P < 0.05) by FC. Acetic, proprionic and butyric acid contents in colon contents were increased by feeding FC, while valeric and caproic acid content decreased by feeding FP (P < 0.05). Feeding FC and FP had no effect (P > 0.10) on colon histology, pH, fecal consistency score and organ weights. Results suggest that FP and FC have independent effects on newly weaned pigs, while effects appear partly related to changes in gut microbiota. Key words: Enteric fermentation, fiber, gastrointestinal function, protein, pigs