The role of supplemental glycine on broilers performance under subclinical necrotic enteritis
Coccidial co-infection, dietary inclusion of viscous grains and ingredients of animal origin protein are considered important predisposing factors for onset of necrotic enteritis (NE). High dietary glycine levels has been shown to increase the intestinal 'C. perfringens' population in broilers (Dahiya et al. 2005). As the causative agent for NE, the spore germination of 'C. perfringens' can be activated by the spore cortex-lytic enzyme (SCLE) coded by SleC thus to cause gastrointestinal disease. Investigations have shown that glycine forms a conjugated compound with bile salts playing a critical role in Clostridial germination (Sorg and Sonenshein 2008). This compound is recognized by the germinant receptor, CspC and is responsible for cleaving the N-terminal propeptide of SleC, expressing mature SCLE to activate its hydrolase activity. The current study assessed the impact of a high dietary glycine inclusion on performance of broilers under subclinical necrotic enteritis challenge.
Effect of Pasture and Feed Additives on Performance and Egg Quality in Ranging Laying Hens
Free-range egg production is rapidly growing in Australia with an estimated retail value market share of 48% (AECL, 2014). Laying hens exposed to pasture range may experience reduced performance, poor enteric health and increased mortality (Ruhnke et al., 2014). In addition, egg quality can also be affected, indicated by the increased number of damaged and misplaced eggs as well as decreased egg shell quality (Kijlstra et al., 2009). These effects may be related to excessive fiber digestion and reduced nutrient uptake. The addition of multi-enzymes or organic acids to free-range layer diets may improve the digestion of nutrients, thus increasing performance, gut health and egg quality. A study was conducted to investigate the effect of range types and feed additives on performance and egg quality of ranging laying hens.
Roles of dietary fibre and ingredient particle size in broiler nutrition
Increasing the structural components in the diet, namely through including coarse grain particles in diets and manipulating the dietary fibre composition, has been shown to improve gut health, feed utilisation and production efficiency. This is primarily because structural components physically stimulate activity in the fore gut. An example of this is dietary non-starch polysaccharides (NSP), namely insoluble NSP, which have been shown to instigate beneficial effects on gut health, litter quality and nutrient utilisation, by increasing crop and gizzard activity, stimulating digestive enzyme production and enhancing bacterial fermentation in the hind gut. However, there is a lack of consistency with regard to the direct effects of dietary fibre on chicken health and production. The aim of this review therefore is to explore the impact of feeding different sources of fibre and different size grain particles on gut health and microflora, nutrient utilisation, performance and litter quality in broilers.
The Effect of a Plant Alkaloid Supplement on Performance of Broilers Under Necrotic Enteritis
Necrotic enteritis (NE) in broilers is caused by Clostridium perfringens. The disease may result in significant economic loss and is currently controlled in Australia by feeding low doses of antibiotic growth promotors (AGP). Alternatives to AGP have been sought since the EU ban of AGP use in livestock. The phytogenic feed additive (Sangrovit® Extra) based on quaternary benzophenanthridine and protopine alkaloids (QBA+PA) shows potential as an AGP alternative that has been reported to be anti-inflammatory, anti-microbial and immunomodulating (Khadem et al., 2014).
Effect of litter material and dietary fibre on gut development, gut microflora and performance in broilers
A feeding study was conducted to compare the effects of litter material, dietary fibre and sex on growth performance, organ development, mucosal morphometry and gut microbial communities in broilers. Seven hundred twenty day old Cobb chicks were allocated to 24 floor pens in a 2 x 2 x 2 factorial design with 3 pens of 30 birds per replicate (3 pens of males and 3 pens of females). Factors were: litter material, paper or hardwood shavings; dietary fibre, low or high and sex. Diets consisted of wheat, soybean meal, meat meal, expeller canola meal, poultry fat, vitamin and minerals. Birds and feed were weighed on days 7, 21, and 35. Low fibre groups contained no oat hulls whereas high fibre groups contained 70 g/kg oat hulls. Birds grown on hardwood shavings had larger gizzards (P < 0.01) and a more favorable FCR (P < 0.03) than those grown on paper litter at 35 d. Dietary oat fibre was more beneficial in birds reared on paper litter than hardwood shavings as evidenced by significant fibre by litter interactions at 35 d for FCR (P < 0.02) and caecal 'C. perfringens' counts (P < 0.01). Dietary oat fibre improved body weight at 7 d (P < 0.04), and lowered gizzard pH (P < 0.02) at 35 d. The results suggest that the combination of clean paper litter with high oat fibre diet may be beneficial in enhancing gut health in broilers.
Effect of seed source and pelleting temperature during steam pelleting on apparent metabolizable energy value of full-fat canola seed for broiler chickens
Eleven canola seed (CS) samples were collected from different commercial feedmills and crushing plants in Australia and analyzed for nutrient profile. Six of these samples were selected to determine the effect of seed chemical composition and pellet temperature (PT) during steam pelleting on apparent metabolizable energy corrected for nitrogen (AMEn) values of CS for broiler chickens using a 6 × 2 factorial arrangement of treatments. The CS samples were incorporated into a corn-soybean meal diet at 15% by replacing energy-yielding ingredients, and diets were steam pelleted at either 75 or 90°C. A total of 420 18-day-old male broiler chicks (Ross 308) was assigned to 14 experimental diets replicated 6 times, with 5 chicks per cage. After a 5-day diet acclimation period from d 18 to 22, excreta were collected for 72 h using the substitution method to determine AME and AMEn. There was no interaction of seed source and PT for ileal digestible energy (IDE), AME, or AMEn values of CS (P > 0.05). PT did not affect energy availability of CS (P > 0.05) but increasing the PT improved the pellet durability index of the diets by approximately 5.0 percentage points. A significant effect of seed source was detected for all the energy utilization values of CS (P < 0.05). The IDE, AME, and AMEn values of seed samples ranged from 5,239 to 5,645, 4,728 to 5,071, and 4,501 to 4,791 kcal/kg of DM, respectively. The mean AMEn values were 4,664 kcal/kg of DM, indicating a 5.7% reduction compared with AME values. There was a negative correlation between protein and fat content of the seeds (r = −0.93, P = 0.001), and, consequently, AMEn (r = −0.32, P = 0.009). AMEn values were positively correlated with fat content of CS (r = 0.649, P = 0.001). These results indicate that fat and protein content and fiber components may have a considerable effect on energy availability of CS for broiler chickens.
Maintaining Gut Health: Novel Approaches
Gastrointestinal health and homeostasis in broilers is important from an economic point of view. Yet, it is not well understood with respect to microflora-host interactions and the effect of infection and immune response on digestive efficiency. There are many conditions that have been named to indicate gastrointestinal health problems. These include diarrhoea, coccidiosis, malabsorption syndrome, wet droppings, sticky droppings, dysbacteriosis, acid-base imbalance, intestinal colibacillosis and necrotic enteritis. Wet litter is described as litter with moisture content above 35%. This is deleterious as it leads to footpad dermatitis, folliculitis, breast blistering, coccidiosis, necrotic enteritis and blindness caused by ammonia production. The etiology of gastrointestinal disturbance is often multifactorial involving protozoan and nematode parasites, mycotoxins, bacteria, viruses, nutrient imbalances, and anti-nutritional factors.
Impact of a Macleaya cordata-derived alkaloid extract on necrotic enteritis in broilers
Necrotic enteritis (NE) causes significant economic losses in the broiler chicken industry, especially in birds raised without in-feed antibiotics. A standardized blend of plant-derived isoquinoline alkaloids (IQA) derived from Macleaya cordata has shown to have anti-inflammatory potency and promoted animal productivity. This study investigated the effects of IQA supplementation on broiler chickens under NE challenge. A 2 × 2 factorial arrangement of treatments was employed with factors: NE challenge (no or yes), and additives (no additive or IQA at 0.15 g/kg) in starter, grower, and finisher diets. Birds were challenged with Eimeria spp. on d 9 and 10⁸ to 10⁹Clostridium perfringens on d 14. Each treatment had 7 replicate floor pens with 17 birds each. NE challenge negatively affected growth performance, livability, and carcass traits. Regardless of challenge, IQA increased feed intake and gain on d 24 (P < 0.05) and 35 (P < 0.01) and improved FCR (P < 0.05), flock uniformity (P < 0.01) and breast meat yield (P < 0.001) on d 35. Supplementation of IQA also reduced lesions in the duodenum (P < 0.05), jejunum (P < 0.001), and ileum (P < 0.001). This study suggests that IQA may protect broilers from NE indicating its role as a promising antibiotic alternative.
Feed particle selection and nutrient intake altered by pecking stone consumption and beak length in free-range laying hens
The present study investigated the effects of pecking stones on feeding behaviour of hens from 16 to 46 weeks of age. Eighteen flocks of Hy-Line Brown hens were housed in 2 commercial free-range housing systems. Farm A housed 10 flocks of beak trimmed (infrared beak treatment) hens in fixed sheds. Farm B housed 8 flocks of hens with intact beaks in mobile sheds. On each farm, flocks were equally assigned to control groups (no access to pecking stones) and treatment groups (access to pecking stones). Data were evaluated every 10 weeks. At each time point, 10 hens per flock were housed in individual pens, and each hen was provided with 250 g of mash diet and ad libitum water for 24 h. After 24 h, feed samples were collected and used to determine 24-h feed intake. Nutrient and particle selection was measured by subtracting nutrients and particles present in the leftover feed from the vaules obtained in the offered feed and expressed the change (Δ). In addition, pecking stone consumption was recorded for each flock. Data were analysed separately for each farm using fixed effects of pecking stone availability and hen age. Spearman's rho correlation coefficients and linear regression models were constructed to evaluate the relationship of beak length and pecking stone usage, discrete mean particle size (dMEAN) consumption (Δ dMEAN), and Δ nutrient intake. Hens with access to pecking stones consumed significantly lower quantities of large feed particles (>2.8 mm) on farm A (P = 0.029) and selected significantly more fine particles, on farm B (P = 0.013). Overall, positive relationships (P = 0.001) between beak length and pecking stone consumption, Δ dMEAN, and Δ phosphorus consumption were observed. In conclusion, pecking stone consumption resulted in reduced selection and consumption of feed particles in hens housed on both farms. Further research is warranted to investigate the effect of pecking stones on sensory innervation of the beak.
Upregulation of genes encoding digestive enzymes and nutrient transporters in the digestive system of broiler chickens by dietary supplementation of fiber and inclusion of coarse particle size corn
Background: Measures to improve bird performance have been sought due to the imminent phase out of in-feed antibiotics in poultry and continued demand for higher poultry feeding efficiency. Increasing grain particle size and dietary fibre may improve gizzard function, digestive efficiency and nutrient absorption. This study was conducted to evaluate the effect increased particle size of corn and inclusion of sugarcane bagasse (SB) on mRNA expression of genes encoding digestive enzymes and nutrient transporters in broilers. Results: A total of 336 day-old Ross 308 males were assigned in a 2 × 2 factorial arrangement of treatments with corn particle size - coarse 3576 μm or fine 1113 μm geometric mean diameter, and SB - 0 or 2% inclusion. Feed conversion ratio (FCR), weight gain and feed intake were measured from d 0-10 and d 10-24. The relative gizzard weight and mRNA expression of genes encoding digestive enzymes and intestinal nutrient transporters were measured on d 24. During d 10-24, a particle size × SB interaction was observed for FCR (P < 0.01), where birds fed coarsely ground corn (CC) with 2% SB had lower FCR than those fed CC without SB. A particle size × SB interaction was observed for both expression of pepsinogen A and C (P < 0.01) which were negatively correlated with FCR on d 24. Addition of 2% SB upregulated pepsinogen A and C only in CC fed birds. Further, 2% SB also upregulated pancreatic amylase (AMY2A) and intestinal cationic amino acid transporter-1 (CAT1). Inclusion of dietary CC upregulated duodenal amino peptidase N (APN), jejunal alanine, serine, cysteine and threonine transporter-1 (ASCT1), and ileal peptide transporter-2 (PepT2). Conclusion: These results suggest that both SB and coarse particle size modulate expression of genes encoding important digestive enzymes and nutrient transporters and thus are directly related to bird performance. These findings provide insights into the combination effects of dietary fiber and particle size in the future management of broiler feeding.