P.F. Varley

Effect of the interaction of seaweed extracts containing laminarin and fucoidan with zinc oxide on the growth performance, digestibility and faecal characteristics of growing piglets

Seaweed extracts (SWE) rich in laminarin and fucoidan have shown promise as a supplement for weaned piglets. However, successful application in pig nutrition depends on their bioactivity in the presence of additives such as ZnO. In the present study, a 2 × 2 factorial experiment was carried out to investigate the effect of the interaction between SWE and ZnO on the growth performance, digestibility and faecal characteristics of 192 weaned piglets (6·5 kg). The piglets were penned in groups of 4 (n 12 pens). The study consisted of two phases after weaning: a starter diet period from the day of weaning (0 d) to 21 d and a transition diet period from 21 to 40 d. The dietary treatments were as follows: (1) control diet; (2) control diet+ZnO; (3) control diet+SWE; (4) control diet+ZnO+SWE. Diets containing ZnO improved the faecal consistency of the piglets throughout the experimental period (0-40 d). An effect of the interaction between ZnO and SWE on several variable was observed. The diet containing only SWE or ZnO improved the feed conversion efficiency of the piglets during the transition diet period; however, this effect was not observed when the diet containing both ZnO and SWE was fed. The diet containing only SWE increased the N and organic matter digestibility of the piglets; however, this effect was not observed in the presence of ZnO. An interaction between ZnO and SWE was observed, whereby the faecal counts of Escherichia coli were decreased when piglets were fed the diet containing only SWE, but not when fed the diet containing both SWE and ZnO. In summary, SWE and ZnO improve growth performance when given alone, but not when given in combination. The biological effect of SWE on selected digestibility and faecal characteristics was markedly different when compared with that of ZnO.

Effect of dietary mineral level and inulin inclusion on phosphorus, calcium and nitrogen utilisation, intestinal microflora and bone development

BACKGROUND An experiment was conducted to investigate the interaction between dietary phosphorus (P) level (4 vs 6 g total P kg(-1)) and inulin inclusion (0 vs 20 g kg(-1)) on coefficients of total tract apparent digestibility, nitrogen (N), P and calcium (Ca) utilisation, bone mineralisation, selected gastrointestinal microflora, intestinal volatile fatty acid concentrations and digesta pH in the ileum, caecum and proximal colon. Owing to the design of the experiment, as dietary P level increased, there was also an increase in dietary Ca level in order to maintain a sustainable dietary Ca/P ratio. Entire male finisher pigs (n = 10 per treatment) with a similar initial body weight (51 kg, standard deviation 2.4 kg) were used. RESULTS Inulin inclusion lowered (P < 0.01) Enterobacteriaceae populations in the proximal colon compared with pigs offered diets without added inulin. However, intestinal bacterial populations of Lactobacillus and Bifidobacterium spp. were unaffected. Inulin inclusion had no effect on mineral digestibility or bone mineralisation. Pigs offered low P and Ca diets had lower (P < 0.01) bone mineralisation than pigs offered high P and Ca diets. CONCLUSION Intestinal bacterial populations of Enterobacteriaceae in the proximal colon were lowered by inulin inclusion. Inulin inclusion did not affect P, Ca or N utilisation or bone mineralisation in the finisher pig when offered either a low or a high P diet. Increasing the P and Ca content of the diet led to an increase in bone mineralisation.

The effect of protease and xylanase enzymes on growth performance and nutrient digestibility in finisher pigs.

Two 2 × 2 factorial experiments were conducted to investigate the interaction between xylanase (0 vs. 200 mg/kg) and protease (0 vs. 200 mg/kg) enzyme supplementation on growth performance (Exp. 1) and coefficient of ileal and total tract apparent digestibility in grower-finisher pigs (Exp. 2). One hundred and twenty-eight individual fed pigs (BW = 34.2 kg; n = 32) were assigned to 1 of 4 dietary treatments: basal diet (T1), T1 + xylanase enzyme (T2), T1 + protease enzyme (T3), or T1 + xylanase + protease enzymes (T4). The pigs offered diets containing protease enzymes had reduced daily gain (0.795 vs. 0.840 kg/d; P < 0.05) and final body weight (96.4 vs. 99.1 kg; P < 0.05) compared to pigs offered diets without protease enzymes. Pigs offered xylanase-supplemented diets had reduced daily gain (0.787 vs. 0.848 kg/d; P < 0.05) compared to pigs offered diets without xylanase enzymes. In Exp. 2, the nutrient digestibility experiment consisted of 24 intact male pigs (n = 6; BW = 78 kg), offered identical diets to that offered in Exp. 1. Following the fecal collections, the pigs were slaughtered and digesta samples were taken from the ileum in order to measure apparent ileal N and GE digestibilities. Pigs offered diets supplemented with protease had increased coefficients of ileal digestibility of N compared to pigs offered diets without protease supplementation (0.583 vs. 0.449; P < 0.05). There was a xylanase × protease interaction (P < 0.05) on the apparent ileal digestibility of GE. Pigs offered diets containing protease only had increased apparent ileal digestibility of GE compared to basal fed pigs; however, the ileal digestibility of GE decreased when protease was combined with xylanase. Neither xylanase nor protease enzymes had any effect on total tract digestibility of GE or N. In conclusion, xylanase and protease enzyme supplementation had no positive effects on grower-finisher pig performance.

The effect of protease and nonstarch polysaccharide enzymes on manure odor and ammonia emissions from finisher pigs

A 2 × 2 factorial experiment was conducted to investigate the effect of dietary protease (0 and 200 mg/kg) and xylanase (0 and 200mg/kg) in reducing manure odor and NH(3) from finisher pigs. Sixteen pigs were assigned to 1 of 4 dietary treatments, (i) basal diet, (ii) basal diet + xylanase, (iii) basal diet + protease, or (iv) basal diet + xylanase + protease, for 24 d. The manure samples from pigs offered diets containing protease showed increased (P < 0.05) molar proportions of isobutyric acid, isovaleric acid, valeric acid, and branched-chain fatty acids in contrast to pigs offered diets without protease supplementation. The pigs offered diets with xylanase inclusion had reduced (P < 0.05) manure odor emissions compared to pigs offered diets without xylanase supplementation [598 vs. 1306 European odor units (OuE)/m(3)]. Pigs offered protease-supplemented diets alone had significantly higher NH(3) emissions compared to basal fed pigs. However, NH(3) emissions were reduced when protease was combined with xylanase. In summary, this study indicates that protease supplementation increased protein-derived VFA in manure and also increased manure NH(3) emissions when offered singularly. Consumption of diets containing xylanase reduced manure odor emissions.

Effect of crude protein and phosphorus level on growth performance, bone mineralisation and phosphorus, calcium and nitrogen utilisation in grower-finisher pigs

Two experiments in a 2 × 2 factorial arrangement were conducted to evaluate the effect of crude protein (CP) (130 vs. 200 g/kg) and phosphorus (P) (4.0 vs. 6.0 g total P/kg) level in a phytase supplemented diet (500 FTU [phytase units]/kg) in grower-finisher pigs. Owing to the design of the experiment, as dietary P level increased, there was also an increase in dietary calcium (Ca) level in order to maintain a dietary Ca to P ratio of 1.6:1. In Experiment 1, four diets were fed to 56 pigs (n = 14, initial body weight [BW] 36.7 ± 4.2 kg) to investigate the interaction between CP and P on growth performance, bone mineralisation and digesta pH. Experiment 2 consisted of 16 entire male pigs (n = 4; offered identical diets to that offered in Experiment 1) for the determination of total tract apparent digestibility and nitrogen (N), P and Ca utilisation. There was an interaction between CP and P level on bone ash, bone P and bone Ca concentrations (p < 0.05). Pigs offered low CP–low P diets had a higher bone ash, P and Ca concentrations than pigs offered high CP–low P diets. However, there was no effect of CP level at high P levels on bone ash, P and Ca concentrations. Pigs offered low P diets had a lower ileal pH compared with pigs offered high P diets (p < 0.05). In conclusion, offering pigs a high CP–low P, phytase-supplemented diet resulted in a decrease in bone mineralisation.

The effect of seaweed extract as an alternative to zinc oxide diets on growth performance, nutrient digestibility, and fecal score of weaned piglets

This study investigated if supplementing the diet with seaweed extracts (SWE) containing laminarin and fucoidan would promote growth performance, nutrient digestibility, and fecal consistency in newly weaned piglets during 2 growth phases as compared with ZnO. The experiment was designed as a 2 × 2 factorial with 2 levels of SWE (0 or 300 mg/kg laminarin + 240 mg/kg fucoidan) and 2 levels of ZnO [0 or added (3.1 g/kg for the starter diet and 2.5 g/kg for the transition diet)]. Dietary treatments were (i) basal diet, (ii) basal diet + ZnO, (iii) basal diet + SWE, and (iv) basal diet + ZnO + SWE. Newly weaned 6.5-kg pigs (n = 12; 4 pigs per pen) were offered supplements in a starter diet from weaning (day 0) to day 21 and in a transition diet from day 22 to day 40. There was an interaction (P = 0.005) between SWE and ZnO on G:F whereby pigs supplemented with SWE and ZnO individually had improved G:F when compared with the combination diet. There was an interaction between SWE and ZnO interaction on digestibility of DM (P < 0.01), N (P < 0.01), and NDF (P < 0.01). Pigs offered the SWE diets alone had a higher digestibility of DM, N, and NDF compared with pigs offered the basal diet. In summary, SWE induced a comparable growth performance pattern as obtained with ZnO inclusion. However, this was negated when supplements were offered in combination. Improvements in growth performance of pigs consuming SWE alone may reflect improvements in nutrient digestibility.

Effect of phosphorus level and inulin inclusion in a wheat based finisher pig diet on nitrogen, phosphorus and calcium metabolism and intestinal microflora

Introduction The formulation of commercial grower finisher pig diets supplies excess dietary phosphorus (P) through the high inclusion levels of cereals which generally consist of indigestible P in the form of phytate P. As a result incomplete digestion of P is largely responsible for unnecessary P excretion. Feeding reduced P diets supplemented with non digestible oligosaccharides (NDO) have been shown to promote mineral absorption in the large intestine of both humans and rats. Research data representative of NDO application in pigs are limited. Lopez et al. (2000) suggested that enhanced fermentation in the colon due to NDO feeding, such as inulin, apparently promotes better hydrolysis of phytate and, thus, enhanced colon P and calcium (Ca) absorption in small mammals. Inulin is classified as dietary fibre resistant to complete enzymatic degradation in the small intestine which is selectively fermented by Bifidobacteria and Lactobacilli spp. (Roberfroid et al., 1998). The objective of this experiment is to investigate the interaction between P and inulin level on mineral metabolism and intestinal microflora in a low and high P wheat based diet.