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Fibrolytic enzymes are routinely added to non-ruminant livestock feeds to help degrade the non-starch polysaccharide (NSP) contents and thereby improve feed efficiency. This study investigated the range of xylooligosaccharides (XOS) and monosaccharides produced from four cereal samples (barley, maize, oats and wheat) over a 72 h in vitro incubation using 3 commercially available (AB Vista, Marlborough, Wiltshire, United Kingdom) fibrolytic enzymes, Econase XT, Econase MP1000 and Barley P700, all containing endo-xylanase with other combinations of enzymes. Complete non-starch acid hydrolysis showed there were differences between cereals in the total monosaccharide (P < 0.01). There was a cereal x enzyme x incubation time 3-way interaction in the generation of XOS (xylotetraose, xylotriose and xylobiose) (P < 0.01) indicating the generation of XOS varies dependent on both the cereal and the enzyme used. The enzymes failed to generate any detectable xylose from maize. For xylose there was also a cereal x enzyme x incubation time 3-way interaction (P < 0.05). Econase XT generated the greatest quantity of xylose, with 38% of available xylose from wheat being released after 72 h, 11% from barley and 9% from oats, whilst no xylose was detected from maize using any of the 3 commercial enzyme preparations. For arabinose and galactose production there was a cereal x enzyme x incubation time 3-way interaction (P < 0.01), whilst glucose release was only significantly affected by cereal (P < 0.05) or time (P < 0.05). These findings suggest that the fibrolytic enzymes tested have some specificity for certain cereals and therefore it might be possible to optimise the combinations used in animal feeds, to help maximise the feed efficiency of livestock.

The objective of the present broiler study was to study the relationship between peptide tyrosine-tyrosine (PYY), cholecystokinin (CCK) and short-chain fatty acids (SCFA) in the blood and caecal contents, and whether a period of fasting followed by reintroduction of feed influences this relationship compared with an ad libitum fed control. A total of 72 male broilers with 37-days of age (Ross 308) were randomly distributed into two experimental groups, with continuous illumination. Group 1 (n = 36) were fasted for 12 h followed by re-feeding, and Group 2 (n = 36) were feed ad libitum. Twelve animals per group were sacrificed immediately prior to reintroduction of feed to the fasted animals (T0h), and this was repeated at 3 h (T3h) and 6 h (T6h) after feed reintroduction. Blood samples were collected for PYY and CCK analyses, and short-chain fatty acids were analysed in blood and caecal contents. For PYY and CCK, the interactions between the feed administration, ad libitum or fasted, and the time after feed reintroduction were significant (P

It has long been considered that an injectable iron supplementation within 48–72 h of birth would sufficiently meet the iron requirement for rapidly growing piglets and the prevalence of iron deficiency and, therefore, the anaemia in nursery barns would not be one of the major issues that compromise the genetic growth potential of young pigs. However, a number of recent commercial farm surveys indicate a significant prevalence of iron deficiency and anaemia in young pigs reared in indoor pork production systems along with a negative relationship between iron status of piglets and body weight gain during the first 6 weeks postpartum. Therefore, this review aims to provide (1) the underline physiology for how iron homeostasis is maintained through regulation of iron absorption capacity, (2) iron status of sows and piglets, (3) supplemental iron in relation to physiological response of pigs, (4) dietary factors involved in the regulation of iron absorption capacity, and (5) possible nutritional strategies to improve iron absorption capacity and hence iron status of piglets.

The objective of this research was to test the hypothesis that calculated values for standardized total tract digestibility (STTD) and retention of Ca and P are not different between gestating sows and growing pigs. A total of 32 gestating sows (day of gestation = 40) and 32 castrates (body weight = 19.8 kg) were placed in metabolism crates. Two diets were formulated to contain 9.8 or 29.4 g/kg phytate. Diets were formulated based on corn, soybean meal, Ca carbonate, and dicalcium phosphate and the high-phytate diet also contained 400 g/kg full-fat rice bran. A Ca-free diet and a P-free diet were used to determine basal endogenous losses of Ca and P. Feces and urine were collected for 4 days after 4 days of adaptation. Results indicated that basal endogenous losses of Ca and P from gestating sows were greater (P

The objective of this study was to investigate how xylanase-induced changes in soluble sugar, short chain fatty acid (SCFA) and microbial content of the gut might be linked to broiler performance. A 42-day experiment was conducted using 328 male Ross 508 broiler chicks divided into two treatment groups, fed wheat-based diets with or without xylanase (0 or 16,000 BXU/kg). Each group had 8 replicate pens (13 birds per pen), with 3 additional replicate sampling pens per treatment (20 chicks per pen). Early body weight differences were shown, with xylanase-fed birds being 21 g ( P = 0.02) and 39 g ( P = 0.10) heavier at days 11 and 21 than control birds. Over the entire 42 day experimental period, body weight gain (BWG) and feed conversion ratio (FCR) with xylanase supplementation were not significantly different from the control, possibly due to the high performance of birds in both treatments. Xylanase supplementation increased ( P 0.05) soluble arabinose and xylose residues in the ileum and decreased ileal viscosity of birds at all ages, suggesting arabinoxylan degradation to soluble oligosaccharides. Xylanase had no significant effect on soluble sugar residue concentration in the caecum at any age. Irrespective of treatment, caecal soluble sugar residue content was considerably higher in 11 day-old birds, possibly illustrating poorer nutrient digestion and absorptive capacity of young birds. The proportion of xylose and arabinose residues in total caecal soluble sugars decreased ( P 0.001) at day 21, suggesting greater utilisation by resident bacteria. At day 42, compared to the controls, xylanase-fed birds had higher ( P = 0.01) Bifidobacterium spp. levels (5.7 e +10 versus 8.1 e +9 ), increased quantities of acetic ( P = 0.002) and butyric acids (P P = 0.03) lactic acid levels in the caeca. At all ages, xylanase treatment reduced ( P = 0.04) the proportion of branched chain volatile fatty acids in total SCFA, suggesting a reduction in protein fermentation. These findings suggest that greater degradation of wheat arabinoxylan with xylanase can enhance colonisation of specific bacteria and production of SCFAs in the caeca, an event that may relate to improved broiler performance.

The objective of this study was to evaluate the effect of xylanase on performance, nitrogen corrected apparent metabolizable energy (AMEn), relative gastrointestinal (GIT) weights, caecal fermentation and microbiota profile of turkeys fed wheat-barley-rye based diets. Four hundred eighty female Hybrid Converter turkey poults (1-day-old) were placed in one of two experimental treatments: a control diet (CTR) formulated to be marginally deficient in metabolizable energy, and the same diet supplemented with 16,000 BXU/kg of xylanase (XYL). Treatments had fifteen replicate pens per diet, with 16 birds each. Feed was supplied in four phases of three weeks per phase. On d 1, 21, 42, 63 and 84 body weight was measured, and feed intake (FI) recorded. Body weight gain (BWG) and feed conversion ratio (FCR) were then calculated. On d 84 the last day of the study excreta samples were collected to determine AMEn. The profile of volatile fatty acids (VFA), lactic acid and branched-chain fatty acids (BCFA) in addition to the microbial community structure by the percentage of guanine plus cytosine (G + C) profile method in the caecal digesta were analysed on d 84. Statistical comparisons were performed using one-way ANOVA (JMP Pro 12). Xylanase supplementation over the 12 week study improved FCR (P

This study investigated the effects of xylanase and fiber on growth response, cecal short-chain fatty acids (SCFA) production, and cecal microbiota diversity in broilers. A total of 180 day-old chicks (Cobb 500) were randomly distributed in 30 pens (6 birds/pen). Six dietary treatments were tested using a completely randomized design in a 3 × 2 factorial arrangement (n = 5). The treatments included 3 levels of wheat bran (WB) as an additional fiber source in corn soybean meal-based diet, supplemented without or with xylanase (0.1 g/kg Econase-XT) besides 500 FTU/kg phytase and fed in 2 phases (starter, d 0–21 and finisher, d 22–35) in mash form. The three levels of WB used in this study were included at the concentration of 0 g/kg (WB 0%), 50 g/kg (WB 5%), and 100 g/kg (WB 10 %) in diet. Xylanase supplementation significantly (P

This study was conducted to investigate the effects of xylanase (XYL) and xylo-oligosaccharide (XOS) supplementation on the growth performance and faecal bacterial community composition in growing pigs over time. In this 35-day trial, a total of 464 grower pigs with an average initial body weight (BW) of 14.5 kg (SD ±1.56 kg) were blocked into mixed sexed pens of 4–5 pigs balanced for BW, sex and litter origin. Pens were randomly allocated to 1 of 4 dietary treatments in a 2 × 2 factorial treatment arrangement with 2 concentrations of supplementary XYL (0 and 0.15 g/kg) and XOS (0 and 0.20 g/kg). On a weekly basis, pen feed intake and pigs were weighed to calculate pig performance. Faecal samples from 32 male pigs were collected on days 1, 14 and 35 of the trial and analysed to profile the bacterial communities through 16S ribosomal ribonucleic acid (rRNA) sequencing of the V4 region on the MiSeq platform (Illumina). There was no effect of XYL on pig performance, nor was there an interaction between XYL and XOS. Pigs supplemented with XOS had a poorer gain to feed ratio during the first week (Day 1–7) of the trial (P

The objective of the present study was to investigate the effects of age on the apparent ileal calcium (Ca) digestibility of limestone for broiler chickens. Six treatment groups of different ages, namely days 1–7, 8–14, 15–21, 22–28, 29–35 and 36–42, were utilised. A maize-based diet (crude protein, 79 g/kg) containing limestone as the sole Ca source and, supplying 9.0 g/kg Ca, was fed to six replicate cages of broilers during each of the six periods. The birds were fed a commercial broiler starter diet until the introduction of the assay diet, except the day 1–7 age group. Ileal digesta were collected on day 7 (twelve birds per cage), 14 (ten birds per cage), 21 (eight birds per cage), 28 (six birds per cage), 35 (six birds per cage) or 42 (six birds per cage). A secondary objective was to examine the influence of dietary protein content on Ca digestibility. An additional diet containing a crude protein content of 153 g/kg was developed and fed to six replicate cages (eight birds per cage) from day 15 to 21 post-hatch. The birds in the age group of 15–21 days and fed the 79 g/kg crude protein diet served as the control treatment. Titanium dioxide (5 g/kg) was included in all diets as an indigestible marker for apparent ileal digestibility measurements. Total tract Ca retention, pH of gizzard digesta and relative weights of gizzard and gizzard digesta were also measured. Apparent ileal Ca digestibility coefficients declined linearly (P 0.05) on the apparent ileal digestibility and retention of Ca. Increasing dietary protein had no effect (P > 0.05) on the relative weights of gizzard and gizzard digesta. In conclusion, the present results showed that the Ca digestibility of limestone in broilers, fed a maize-based diet with limestone supplying 9 g/kg Ca, declined with advancing age.

The effects of xylanase supplementation on production performance, carcass traits, caecal volatile fatty acid and peptide YY concentration in serum of broiler chickens fed maize–soybean based diets were tested in a 42 d experiment. Dietary metabolizable energy (AME, N uncorrected) was decreased in the experimental diets by 0 (E 1 ), 230 (E 2 ) and 420 kJ/kg (E 3 ). Each of these diets was supplemented with 0 (X 1 ) or 16,000 units/kg (X 2 ) of a commercial xylanase. The objective was to ascertain if the xylanase could spare dietary energy for growth through its effects on peptide YY concentration in blood. Reduction of dietary AME depressed body weight gain (P=0.014), deteriorated feed conversion ratio (P=0.018) and decreased carcass yield (P=0.0001) over 42 d. Irrespective of the level of supplemental xylanase, breast meat yield was the poorest in the E 2 groups (P=0.003). Supplementation of xylanase had no effect on body weight gain, feed consumption, feed conversion ratio (feed consumption: body weight gain) and carcass traits (P>0.05). Low energy diets increased total volatile fatty acids (VFA) in caeca (P=0.0001). Xylanase supplementation tended to decrease caecal VFA irrespective of dietary AME (P=0.07). Increasing dietary AME reduced Salmonella (P=0.018) and Escherichia coli (P=0.019) and increased Enterobacteriaceae (P=0.012) populations in caeca. Reduction in dietary AME decreased glucose (P=0.0001) and cholesterol (P=0.012) in serum, particularly in the E 3 groups. Serum glucose increased due to xylanase supplementation in the E 1 and E 3 groups but not in the E 2 group (energy × xylanase P=0.0001). Supplementation of xylanase to the E 2 groups decreased serum cholesterol as compared with the E 1 and E 3 groups (energy × xylanase P=0.002). On the other hand, xylanase supplementation decreased serum concentrations of protein in the E 1 and E 2 groups (energy × xylanase P=0.0001) and uric acid in the E 2 and E 3 groups (energy × xylanase P=0.006). Serum insulin reached a maximum (P=0.0001) in the E 2 group irrespective of xylanase supplementation and added xylanase increased serum insulin (P=0.0001) at all dietary AME levels. There was an interaction between dietary AME and supplemental xylanase on serum peptide YY concentration (P=0.0001) which suggested that the xylanase induced increase in the serum peptide YY concentration was dependent on dietary energy density. It was concluded from the present investigation that supplementation of xylanase to a maize–soybean based diet of broiler chickens may consistently increase serum peptide YY concentration and improve metabolic indices like serum insulin levels. However, the results also indicated that with maize–soybean based diet, such positive effects on metabolic indices may not translate into performance if the diet is compromised with energy by 230 kJ/kg or more.

The use of enzymes has increased dramatically in the last 20 years, and yet the fact that perhaps one of their most important actions is in mediating the size and composition of microbial populations is still largely unrecognized. As the public press for increasingly antibiotic (and by extension coccidiostat) free diets, it is clear that this under-investigated facet of enzyme action warrants far greater scrutiny. Until quite recently it was assumed that the intestinal microbiota were simply reactive to the nutrients left behind after digestion had completed. However it now seems that intestinal microbial population size and composition clearly plays a very large role in determining the extent of digestion accomplished by the host and by extension, growth rate and efficiency. This is becoming increasingly becoming apparent with the advent of new molecular techniques coupled with statistical methods which are beginning to identify desirable and undesirable clusters of organisms as far as good performance is concerned, although the variability in techniques utilised is hampering progress. The fact that exogenous enzymes not only influence the partitioning of nutrients to the host but also, through their action, produce nutrients for specific populations of bacteria, means that they are multifactorial in their effect. As a result their effects are influenced by many other factors such as presence of antibiotics, health status/disease challenge of the animals and quality of ingredients fed. Understanding of such interactions will lead to a more predictable and profitable outcome for the end user.

An experiment of 35 d duration was conducted to evaluate the effects of dietary supplementation (1 g/kg) of yeast ( Saccharomyces cerevisiae ), yeast protein concentrate (YPC) and YPC-pellets on production performance of heat stressed broilers (Cobb 400, n = 128). Ambient temperature was constantly maintained at 32–34 °C. At 21 d, all the birds were orally challenged with Salmonella enteritidis (10 × 10 7 colony forming units/ml) and the numbers of total Salmonella were enumerated in excreta at periodic intervals. Dietary supplementation of YPC and YPC pellets improved body weight at 21 and 35 d of age (P = 0.001) and FCR in 35 d (P = 0.001). Salmonella numbers decreased in the pooled digesta and excreta due to dietary supplementation of yeast and YPC additives (P 0.05) particularly in the YPC-pellets group. E. coli numbers in digesta also decreased in the treated groups (P = 0.011). Humoral immune response against Newcastle disease was improved by dietary supplementation of YPC and YPC-pellets at 14 d (P = 0.028), 28 d (P = 0.001) and 35 d (P = 0.001). The effect of dietary yeast supplementation on humoral immune response was evidenced on 35 d of age. Severity of panting was comparatively less when the YPC additives were supplemented in diet and this was corroborated by a lower serum CO 2 concentration (P = 0.019) in the YPC and YPC-pellets groups at 21 d of age as compared with the control. Supplementation of YPC and YPC-pellets increased serum T3 level (P = 0.001) at 21 d and decreased serum cortisol at 21 and 35 d vis-a-vis the control group (P = 0.001). Yeast supplementation was also as effective as the YPC additives in reducing serum cortisol level. Villus height increased by supplementation of YPC-pellets as compared with the other dietary groups (P = 0.008) although the implication of this increment was not discernible in terms of production performances. Although, converting the yeast protein concentrates into YPC-pellets did not offer any substantial advantage in terms of enhancing production performance of the heat stressed broilers, it may be concluded that YPC additives may effectively sustain the production performance in heat stressed broilers than the conventional yeasts probably by modulation of the levels of circulatory thyroid hormones and cortisol.

The purpose of this work was to study variation in viscosity of different grain samples using different extraction methods, and to study effect of heat treatment on viscosity. A total of 80 samples of wheat, oats and barley harvested at two locations were analysed for physical appearance, fibre content, and in vitro viscosity using water (WEV), acidic buffer (AEV), HCl/NaHCO 3 buffer with pepsin and pancreatin added (IDV) or the Avicheck™ method (FFV). A transformation where the natural logarithm of the relative viscosity value was divided by the concentration of the sample in liquid was shown to give stable values over a wide range of sample concentrations in liquid for WEV and IDV. Barley and oats had similar viscosities although there was considerable variation between samples, while viscosity was much lower and with less variation between samples for wheat. Heat treatment in an autoclave at 100°C for 5 min increased WEV for all samples, but IDV increased for oats only as a consequence of heat treatment. Although WEV was much lower than IDV, the correlation between these two viscosities was high (0.95, P P

Exogenous enzymes which, for the purpose of this paper, include carbohydrases and phytase, are now extensively used throughout the world as additives in non-ruminant diets. The chemical effects of these enzymes are well understood, but the manner in which their benefits to the animal are brought about is still under debate. Regardless, the overall effect of carbohydrase enzyme use is to reduce the variation between good and bad samples of a target ingredient substantially. The net benefit is that the nutrient requirements of the animal are met more frequently, and with diets of lower nutrient concentration. Variation in animal performance from flock to flock is also reduced. Phytase, on the other hand, was originally used for one express purpose — to increase the availability of plant phytate phosphorus, which reduces phosphorus pollution and allows reductions in the amount of inorganic phosphate used. Further benefits of phytase utilisation on energy and amino acid availability have recently been identified which will, with appropriate dietary modifications, allow for further improvements in resource utilisation. Current issues of concern for all enzymes include variability in response. Substrate variability and interactive factors significantly influence the response to exogenous enzymes. Currently, there are methods which take such factors into account and allow for prediction of optimum dose of carbohydrase enzymes in wheat and barley based diets and efforts are underway for maize based diets or for optimisation of the use of phytase. Future research in these areas will allow for more efficient use of the current enzymes and development of more efficient future products. Development of more thermotolerant enzymes will also allow their use in diets where they currently cannot be applied.

The efficiency of utilisation of wheat, oats, barley and rye by poultry is often limited by the presence of antinutritional factors (ANFs). Such ANFs are commonly referred to as non-starch polysaccharides, classified as arabinoxylans and β-glucans. The arabinoxylans, which consist of a linear backbone of xylose substituted with arabinose, are responsible for the bulk of the problems encountered in birds fed wheat or rye based diets, whilst the β-glucans, a linear polymer of glucose with kinks in its structure, are responsible in oats and barley. However it is only the high molecular weight arabinoxylans and β-glucans that are responsible. Both β-glucans and arabinoxylans exert their negative effects on digestion by creation of very large entanglements which result in an elevation of viscosity of the small intestine. Such an elevation results in a reduction in the rate of digestion and absorption of nutrients, an elevation of microbial activity in the intestine, a reduction in feed intake and increased litter moisture. The application of relevant and effect xylanases and β-glucanases can alleviate these problems by reducing the molecular size of the target substrate, which in turn reduces the viscosity of the intestine and hence enables more rapid digestion. It is unlikely that exogenous enzymes reduce the β-glucans and arabinoxylans to their constituent sugars since relatively few catalytic events are necessary to reduce the molecular size and hence viscosity of these complexes. A more detailed understanding of the structure of these viscous complexes as they appear in the intestine will enable the design of more specific enzymes for poultry feeds.

A barley-based diet for broiler chickens was supplemented with a commercial feed enzyme product (Avizyme SX®, containing Trichoderma longibrachiatum β-glucanase) at 0, 1 and 10 g kg−1 and pelleted after conditioning at 75, 85 or 95°C for either 30 s or 15 min in a 3 × 3 × 2 factorial design. The pelleted feeds were analysed for β-glucanase activity, starch, total and soluble β-glucan and non-starch polysaccharides (NSP) and fed to 1-day-old male broiler chickens for a 19 day period, at the end of which, weight gain, feed intake and the incidence of vent pasting were recorded. On Day 19, four birds per treatment were killed and digesta viscosity and β-glucanase activity in the proximal part of the small intestine evaluated. Conditioning at 75°C for 30 s reduced β-glucanase activity compared with control mash diets to 66% of initial activity, whereas 15 min conditioning at 75°C reduced recovery to 49%. At 85°C with 30 s and 15 min conditioning, the recoveries were 56% and 31%, and at 95°C, these were 16% and 11%, respectively. There was a negative quadratic effect of conditioning temperature and a positive linear effect of enzyme level on liveweight gain and feed efficiency. Conditioning time did not influence chick performance and there were no treatment effects on feed intake. The incidence of vent pasting decreased linearly with increasing enzyme inclusion rates and was significantly higher after conditioning for 15 min compared with 30 s. Dietary β-glucanase correlated linearly with digesta β-glucanase activity and the slope of the relationship indicated full recovery of the enzyme in the small intestine of the birds. Digesta β-glucanase activity correlated linearly with viscosity, which in turn correlated highly with bird performance. Despite this, dietary β-glucanase values required transformation to their logarithms before they could be used to accurately predict bird performance. The results from this experiment suggest that partial enzyme inactivation occurs at pelleting. The magnitude of the inactivation depends on the pelleting conditions employed, with higher temperatures and prolonged conditioning times increasing inactivation. However, in this experiment, bird performance was only affected when feeds were pelleted at temperatures over 85°C. The viscosimetric method used for measuring β-glucanase activity in the feeds proved to give a good estimate of the in vivo activity based on digesta viscosity. However, values obtained with this method needed a logarithmic transformation for accurate prediction of chick performance, thereby reducing sensitivity with values normally encountered in feed. Digesta viscosity was a good indicator of bird performance.