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Swick, Robert
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Given Name
Robert
Robert
Surname
Swick
UNE Researcher ID
une-id:rswick
Email
rswick@une.edu.au
Preferred Given Name
Robert
School/Department
Poultry Hub Australia
82 results
Now showing 1 - 10 of 82
- Publication
- PublicationThe role of supplemental glycine on broilers performance under subclinical necrotic enteritisCoccidial 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.
- PublicationFactors affecting energy metabolism and evaluating net energy of poultry feedDifferent energy evaluating systems have been used to formulate poultry diets including digestible energy, total digestible nutrients, true metabolizable energy, apparent metabolizable energy (AME), and effective energy. The AME values of raw materials are most commonly used to formulate poultry diets. The net energy (NE) system is currently used for pig and cattle diet formulation and there is interest for its application in poultry formulation. Each energy evaluating system has some limitations. The AME system, for example, is dependent on age, species, and feed intake level. The NE system takes AME a step further and incorporates the energy lost as heat when calculating the available energy for the production of meat and eggs. The NE system is, therefore, the most accurate representation of energy available for productive purposes. The NE prediction requires the accurate measurement of the AME value of feed and also an accurate measurement of total and fasting heat production using nutritionally balanced diets. At present, there is limited information on NE values of various ingredients for poultry feed formulation. The aim of this review is to examine poultry feed energy systems with the focus on the NE system and its development for chickens.
- PublicationResponse of growth performance and intestinal microflora to sugar cane bagasse and corn particle size(The World's Poultry Science Association, 2016)
; ; This study was conducted to evaluate growth performance and ileal microflora in response to sugar cane bagasse (lignocellulose) and corn particle size. Three hundred and thirty six Ross 308 male broilers were assigned in a 2 × 2 factorial arrangement of treatments with 2 particle sizes (coarse and fine) and 2 levels of a lignocellulose (0%, 2%). Each treatment had 6 replicate pens of 14 birds from 0-24 d. Feed conversion ratio (FCR), weight gain and feed intake were measured from 0-10 and 10-24 d.
- PublicationNutrient digestibility response to sugarcane bagasse addition and corn particle size in normal and high Na diets for broilersImproving diet digestibility is important to the broiler industry. Therefore, this study focused on optimizing the physical structure of feed ingredients and addition of dietary fiber as strategies to improve nutrient digestibility in low and high sodium diets. A total of 672 day-old Ross 308 male broilers was allocated to 48 pens using a 2 × 2 × 2 factorial arrangement of treatments with 2 particle sizes of corn (coarse 3,576 μm or fine 1,113 μm geometric mean diameter), 2 levels of sugarcane bagasse (SB) (0 or 2%), and 2 levels of Na (0.16 or 0.4%). Protein digestibility coefficient was measured using pooled distal ileal digesta of 3 birds per pen on d 24. Meanwhile, starch and gross energy digestibility coefficients were measured using pooled duodenal, distal jejunal, and distal ileal digesta of 3 birds per pen on d 24. Coarsely ground corn (CC) resulted in improved ileal protein digestibility (P < 0.05). Addition of 2% SB increased starch digestibility in the duodenum (P < 0.05), distal jejunum (P < 0.001), and distal ileum (P < 0.001), and increased protein digestibility in distal ileum (P < 0.01). A significant particle size × SB × Na interaction was observed for ileal energy digestibility (P < 0.05). The SB increased ileal energy digestibility only in birds fed the diet with finely ground corn (FC) and 0.16% Na. These findings demonstrate that SB and CC are able to improve nutrient digestibility. It can be recommended for the poultry industry to use SB and coarsely ground corn in feed to improve the utilization of nutrients.
- PublicationImpact of a Macleaya cordata-derived alkaloid extract on necrotic enteritis in broilers(Oxford University Press, 2017)
; ; ; - PublicationRoles of dietary fibre and ingredient particle size in broiler nutrition(Cambridge University Press, 2018)
; ; ; ; 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. - PublicationImplementation of net energy evaluating system in laying hens: Validation by performance and egg quality
Three experiments were conducted to determine the effect of different dietary net energy (NE) and AMEn ratios (NE:AMEn) on performance, egg quality, and heat production (HP) in laying hens. In experiment 1, 62 Hy-Line Brown hens were fed 2 treatments with 31 replicates from 44 to 54 wk of age. In experiment 2, 600 hens of the same strain were fed 3 treatments from 22 to 42 wk of age with 10 replicates. Both used a completely randomized design. Diets were based on corn, wheat, wheat bran, barley, soybean meal, canola meal, meat and bone meal, and canola oil. In both experiments, the NE:AMEn ratio of diets was increased with higher oil inclusion compared with T1 controls. The AMEn (kcal/kg), NE (kcal/kg), ether extract (g/kg), and CP (g/kg), respectively, on a DM basis in experiment 1 was T1: 3,011, 2,288, 42, 202 and T2: 3,023, 2,374, 81, 203; and in experiment 2, T1: 3,026, 2,324, 25, 187; T2: 2,949, 2,315, 61, 185; and T3: 3,026, 2,397, 73, 181. Increasing the ratio of NE:AMEn decreased feed intake (P < 0.001) and increased egg mass (P < 0.05) in experiment 2 and increased egg weight (P < 0.01), decreased feed conversion ratio (P < 0.01), increased egg albumen % (P < 0.001), and decreased yolk % (P < 0.05) and shell % (P < 0.05) compared with T1 controls in both experiments. Haugh units and yolk color scores were increased with high NE:AMEn in both experiments (P < 0.001; P < 0.01). Experiment 3 was conducted in calorimetry chambers to measure HP in birds fed experiment 2 diets. Increasing the NE:AMEn increased total retained energy (RE), RE as fat, and RE in the body (kcal/kg BW0.75/D) and NE:AME. The results indicate that using oil to increase the NE:AMEn results in improved performance and egg quality and more efficient energy utilization.
- PublicationUpregulation 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 cornBackground: 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.