Gastrointestinal health and function in weaned pigs: a review of feeding strategies to control post-weaning diarrhoea without using in-feed antimicrobial compounds

For the last several decades, antimicrobial compounds have been used to promote piglet growth at weaning through the prevention of subclinical and clinical disease. There are, however, increasing concerns in relation to the development of antibiotic-resistant bacterial strains and the potential of these and associated resistance genes to impact on human health. As a consequence, European Union (EU) banned the use of antibiotics as growth promoters in swine and livestock production on 1 January 2006. Furthermore, minerals such as zinc (Zn) and copper (Cu) are not feasible alternatives/replacements to antibiotics because their excretion is a possible threat to the environment. Consequently, there is a need to develop feeding programs to serve as a means for controlling problems associated with the weaning transition without using antimicrobial compounds. This review, therefore, is focused on some of nutritional strategies that are known to improve structure and function of gastrointestinal tract and (or) promote post-weaning growth with special emphasis on probiotics, prebiotics, organic acids, trace minerals and dietary protein source and level.

Growth performance and nutrient digestibility in pigs fed wheat distillers dried grains with solubles-based diets supplemented with a multicarbohydrase enzyme

The objective was to investigate the effect of supplementing a wheat distillers dried grains with solubles (wheat DDGS)-based diet with carbohydrase enzyme blends on growth performance and nutrient digestibilities in growing and finishing pigs. In Exp. 1, 48 pigs with a BW of 36.5 +/- 1.03 kg (mean +/- SD) were randomly assigned to 24 pens (2 pigs per pen) on the basis of sex and BW, and pigs were randomly allocated to experimental diets (6 pens per diet). Dietary treatments were a positive control (PC) formulated to meet or exceed NRC (1998) nutrient requirements and a negative control (NC) with DE and Lys reduced by 4 and 5%, respectively, from the PC diet and fed without or with an enzyme blend at 2 levels. Level 1 enzyme supplied 2,600 U of xylanase, 1,200 U of beta-glucanase, and 1,300 U of cellulase per kg of diet; level 2 enzyme provided twice the activities for each enzyme in level 1 per kilogram of diet. Chromic oxide was used as an indigestible marker. Pigs fed the NC diet had less (P < 0.05) ADG than those fed the PC diet. Supplementing the NC diet with enzyme blends linearly increased ADG (P < 0.01). The ADFI was not affected by dietary treatment. The PC diet had greater (P = 0.04) G:F compared with the NC diet, but not the enzyme-supplemented diets. Pigs fed the PC diet had greater (P < 0.01) digestibilities of N, GE, and ether extract compared with those fed the NC diet. Addition of level 2 enzyme to the NC diet improved (P < 0.05) digestibilities of DM, N, GE, and ether extract to levels similar (P > 0.05) to those fed the PC diet. In Exp. 2, 4 ileal cannulated barrows (80.8 kg of BW; SD = 0.65) were allotted to 4 diets in a 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments. Experimental diets contained 15 or 30% wheat DDGS and were fed without or with enzyme addition. The enzyme supplement supplied 2,200 U of xylanase, 1,100 U of beta-glucanase, and 1,200 U of cellulase per kg of diet. Apparent ileal digestibilities (AID) of DM, OM, and energy in enzyme-supplemented diets were greater (P < 0.05) than in unsupplemented diets. There was an interaction effect (P < 0.05) of wheat DDGS inclusion level and enzyme supplementation on AID of DM and Ser. Enzyme supplementation improved (P < 0.05) AID of DM in the diet with 30% wheat DDGS but not 15% wheat DDGS. The results shows that multienzyme supplementation of 30% wheat DDGS-based diet improved growth performance and apparent total tract digestibility of DM, N, GE, and crude fiber in growing pigs and AID of nutrients in finishing pigs.

Amino acid digestibility in dry extruded-expelled soybean meal fed to pigs and poultry

The digestibility of AA in dry extruded-expelled soybean meal (DESBM) and regular, solvent-extracted soybean meal (SBM) were determined in pigs and poultry. In the pig assay, 4 Cotswold barrows (average initial BW of 80.4 kg) fitted with a T-cannula at the distal ileum were allotted to 4 semipurified diets in a 4 x 4 Latin square design. Diet 1, a low protein diet (5% casein), was used to quantify endogenous CP and AA losses. Diets 2, 3, and 4 were formulated to contain 35% regular, solvent-extracted SBM; batch 1 of DESBM (DESBM-1); and batch 2 of DESBM (DESBM-2), respectively, as the sole source of protein. The DESBM samples were obtained from 2 different batches but were subjected to the same processing conditions. Chromic oxide (0.3%) was included as a digestibility marker in all diets. Compared with DESBM-1 and DESBM-2, apparent ileal digestibility of DM in SBM was greater (P < 0.05). Apparent and true ileal digestibilities of AA in SBM were greater (P < 0.05) compared with DESBM-2. In the poultry assay, 4 dietary treatments were each assigned to adult cecectomized roosters in a completely randomized design. Treatment 1 was a nonnitrogenous diet (NND; 90% sucrose and 10% vegetable oil) used to estimate endogenous N and AA losses. Treatments 2, 3, and 4 contained SBM, DESBM-1, and DESBM-2 as the only source of protein. Each of these diets was fed in 25-g quantities formulated to provide 5 g of CP from the respective soybean meal source. The SBM had greater (P < or = 0.05) true digestibility for isoleucine, leucine, cysteine, proline, serine, and tyrosine compared with DESBM-1. The results indicate that, relative to regular, solvent-extracted soybean meal, AA digestibilities of different batches of dry extruded-expelled soybean meal varied in pigs and poultry.

Effect of micronized pea and enzyme supplementation on nutrient utilization and manure output in growing pigs

An experiment was done to determine manure output, N and P excretion, and apparent digestibilities of AA, CP, P, and DM in growing pigs fed barley-based diets containing micronized or raw peas with or without supplementation with enzyme containing primarily beta-glucanase and phytase (Biogal S+). Eight barrows (21.5 +/- 1.2 kg of initial BW) fitted with T-cannulas at the distal ileum were used in a 40-d trial and housed in metabolism cages. Pigs were assigned in a replicated 4 x 4 Latin square design to 4 experimental diets: 1) barley-raw peas control (BRP), 2) barley-micronized peas (BMP), 3) BRP plus enzyme, and 4) BMP plus enzyme (BMP+E). Pigs received 2.6 times maintenance energy requirements based on BW at the beginning of each experimental period. During each experimental period, pigs were acclimatized to their respective diets for 5 d followed by a 3-d period of total fecal and urine collection and another 2-d period of ileal digesta collection. Samples were analyzed for DM, AA (diets and digesta only), N, and P. Wet fecal output of BRP plus enzyme-fed pigs tended to be lower (P = 0.07) than the amount produced by BMP-fed pigs. The amounts of dry feces and urine produced were not different among treatments (P > 0.10). Supplementing the BRP and BMP diet with enzyme increased (P = 0.002) the daily P retained per pig. Pigs fed the enzyme-supplemented diets tended to have lower (P = 0.06) fecal P excretion and greater urinary P excretion (P = 0.001) compared with pigs fed the nonsupplemented diets, but total P excretion was not influenced by diet (P > 0.10). Pigs fed the BMP+E diet retained more (P = 0.006) N per day than pigs fed the BMP diet. However, N excretion was not influenced by dietary treatment (P > 0.10), although BMP+E-fed pigs excreted 13.2% less N in the feces compared with those fed the nonenzyme supplemented controls. Inclusion of micronized peas with or without enzyme supplementation did not affect urinary or fecal N excretion (P > 0.10) compared with the BRP. Dietary treatment had no effect (P > 0.10) on ileal or fecal DM or CP digestibilities. Apparent ileal digestibilities of AA were usually lower (P < 0.05) in the BRP diet compared with the other diets. Enzyme supplementation improved P digestibility at the ileal and fecal level. The current results indicate that utilizing micronized peas in barley-based pig grower diets enhances P retention.

Growth performance and carcass characteristics of pigs fed short-season corn hybrids1

An experiment was conducted to determine growth performance, carcass characteristics, and fat quality of growing-finishing pigs fed diets based on short-season corn hybrids. Twenty-four individually housed, Cotswold, growing pigs with an initial BW of 41.4 (SD = 1.4) kg were blocked by BW and sex and randomly allotted from within block to 1 of 3 diets to give 8 replicate pigs per diet. Experimental diets consisted of a control based on barley and 2 diets based on corn as the main energy sources. A 3-phase feeding program for 20 to 50 kg (phase I), 50 to 80 kg (phase II), and 80 to 110 kg (phase III) of BW was used. Diets for each phase contained approximately 3.5 Mcal/kg of DE, with total lysine of 0.95, 0.75, and 0.64% in phase I, II, and III diets, respectively. Average daily gain, ADFI, and G:F were monitored weekly during each phase. Pigs were slaughtered after reaching a minimum BW of 100 kg to determine carcass characteristics. There were no effects of diet on ADG, ADFI, and G:F (0.45 +/- 0.02, 0.34 +/- 0.02, and 0.31 +/- 0.02 for phase I, II, and III, respectively). Carcass length, dressing percent, LM area, loin depth, backfat thickness, belly firmness, and L*, b*, and a* fat color were not different across dietary treatments. Pigs fed one corn variety had no differences in fatty acid profile with barley-fed pigs, whereas those fed the other variety of corn had a greater (P < 0.05) concentration of PUFA in their backfat. The results indicate that growth performance, carcass characteristics, and fat quality of pigs fed diets based on short-season corn hybrids and those fed the barley-based diet were not different.

Low crude protein diets modulate intestinal responses in weaned pigs challenged with Escherichia coli K88

Opapeju, F. O., Rodriguez-Lecompte, J. C., Rademacher, M., Krause, D. O. and Nyachoti, C. M. 2015. Low crude protein diets modulate intestinal responses in weaned pigs challenged with Escherichia coli K88. Can. J. Anim. Sci. 95: 71–78. Effects of dietary crude protein (CP) content on intestinal indicators of infection and diarrhea in pigs challenged with enterotoxigenic Escherichia coli (ETEC) K88 were investigated. Forty piglets [body weight (BW)=6.96±0.45, mean±SD], housed four per pen, were randomly allotted to two diets (five pens per diet): a 22.2% CP or a 17.3% CP supplemented with amino acids. Diets contained the same amount of standardized ileal digestible Lys, Met+Cys, Thr, Trp based on the ideal amino acid ratio. Isoleucine and Val were added to the 17.3% CP diet up to the level in the 22.2% CP diet. All other nutrients were as per National Research Council (1998) specification. Three piglets per pen were serially slaughtered on days 3, 5, and 7 after weaning for evaluation of intestinal hydrolases (data reported elsewhere). On day 8 post-weaning, the remaining pigs were inoculated with 6 mL of ETEC suspension (1010 CFU mL−1) and slaughtered 20 h later. Mucosal-associated ETEC was detected in higher counts (3.17±0.63 log10 CFU g−1 digesta) in 80% of pigs fed the 22.2% CP diet compared with 20% of those fed the 17.3% CP diet in which the counts were also lower (2.00±log10 CFU g−1 digesta). Pigs fed the 22.2% CP diet tended (P=0.09) to have fewer goblet cells with sialomucins in jejunal villi compared with those fed the 17.3% CP diet. The expression of toll-like receptors 4 and 5 was unaffected by diet but the expression of sodium-coupled glucose transporter 1 was higher (P=0.04) in the jejunum of pigs fed the 22.2% CP diet compared with those fed the 17.3% CP diet. The results suggest that feeding a low-CP diet decreases ETEC proliferation and attachment in the intestinal mucosa and this is accompanied by a reduced expression of sodium-coupled glucose transporter 1.

Digestible energy, protein and amino acid content in selected short season corn cultivars fed to growing pigs

The digestible energy (DE), ileal digestible crude protein (CP) and amino acid (AA) contents in two corn cultivars commonly grown in Manitoba were determined using six ileal cannulated barrows (average initial BW of 21.5 ± 0.9 kg). Three samples of each cultivar, each obtained from two locations, were evaluated in six dietary treatments in a 2 × 3 factorial arrangement. Diets contained 97% corn and 0.3% chromic oxide as an indigestible marker, and were assigned to pigs in a 6 × 6 Latin square design. Ileal digesta and fecal samples were collected for determining energy and nutrient digestibilities. Location affected (P ≤ 0.05) ileal digestible indispensable AA, except for lysine and threonine. Cultivar affected (P ≤ 0.05) ileal digestible CP and indispensable AA, except for lysine, phenylalanine and valine. There was an interaction effect (P < 0.05) of location and cultivar on ileal digestible indispensable AA, except for lysine and histidine. Digestible energy, CP and AA averaged 3662 kcal kg-1, 5.95% and 0.40%, respectively, in the dry matter. The content of digestible CP and AA in corn may vary with location and cultivar and this variation should be considered when formulating livestock feeds. Key words: Amino acids, corn, digestibility, energy, pig