Growth, Nutrient Utilisation and Gut Health of Broiler Chickens Fed Sorghum Distillers' Dried Grains with Solubles

The purpose of this thesis was to investigate the nutritional value of sorghum distillers' dried grains with solubles (sDDGS) and ways by which this can be improved. To elucidate the role of application of enzymes in diets containing sDDGS on performance, nutrient utilisation, intestinal function, gut microflora and some health related parameters, four feeding trials were conducted after a comprehensive analysis of sDDGS samples from different production batches. Each experiment has been presented as a stand-alone paper or distinct chapter

Novel Probiotics for Broiler Chickens

The purpose of this thesis was to select beneficial bacteria from the chicken intestinal tract and to screen them for their potential probiotic characteristics in order to use them against pathogenic bacteria, such as 'C. perfringens' and 'Salmonella'. Five experiments (Chapters 3-7) were conducted and out of four potential probiotic candidates, 'L. johnsonii' was eventually selected as a model organism and its effects on bird performance, gut microflora, gut morphology, and antibiotic effect were examined. Throughout this thesis, Cobb, male broilers were used. Each experimental chapter has been presented as a stand-alone paper, thus, this summary will only give an overview of the key findings of the thesis. Chapter 1 briefly describes the background information and justified the importance of research in the topic of interest, leading to the major hypothesis and objectives for conducting the five experiment contained in the thesis. Chapter 2, the literature review, covers the use of probiotics in poultry production, focusing on their modes of action and properties, and their potential as alternatives to in-feed antibiotics. In Chapter 3, four probiotic isolates were selected from 235 lactobacillus isolates of poultry origin using an antagonistic test against 'C. perfringens', 'E. coli' and 'S. sofia'. Quantitative and qualitative measurements revealed that these four candidates, 'L. johnsonii', 'L. crispatus', 'L. salivarius' and one unidentified 'L.' sp., were antagonistic towards 'C. perfringens', 'E. coli' and 'S. sofia' in vitro and were able to survive in feed for 7 days, in water and litter for more than 24 hours under practical production conditions. Chapter 4 presents data the efficacy of delivering 'L. johnsonii', 'L. crispatus', 'L. salivarius' and an unidentified 'Lactobacillus' sp. via feed in manipulating gut microflora environment and production performance was investigated. Results showed that none of the four candidates improved bird performance but they increased the small intestinal weight and tended to reduce the number of enterobacteria in the ileum. Among the four candidates, 'L. johnsonii' was the best in its effects on gut development and gut microflora, thus it alone was to be used in subsequent studies

Characterisation and quantification of changes in odorants from litter headspace of meat chickens fed diets varying in protein levels and additives

The effect of dietary crude protein (CP) and additives on odor flux from meat chicken litter was investigated using 180 day-old Ross 308 male chicks randomly allocated to five dietary treatments with three replicates of 12 birds each. A 5 × 3 factorial arrangement of treatments was employed. Factors were: diet (low CP, high CP, high CP+antibiotic, high CP+probiotic, high CP+saponin) and age (15, 29, 35 days). The antibiotic used was Zn bacitracin, the probiotic was a blend of three Bacillus subtilis strains and the saponin came from a blend of Yucca and Quillaja. Odorants were collected from litter headspace with a flux hood and measured using selective ion flow tube mass spectrometry (SIFT-MS). Litter moisture, water activity (Aw), and litter headspace odorant concentrations were correlated. The results showed that low CP group produced lower flux of dimethyl amine, trimethyl amine, H2S, NH3, and phenol in litter compared to high CP group (P < 0.05). Similarly, high CP+probiotic group produced lower flux of H2S (P < 0.05) and high CP+saponin group produced lower flux of trimethylamine and phenol in litter compared to high CP group (P < 0.05). The dietary treatments tended (P = 0.065) to have higher flux of methanethiol in high CP group compared to others. There was a diet × age interaction for litter flux of diacetyl, 3-hydroxy-2-butanone (acetoin), 3-methyl-1-butanol, 3-methylbutanal, ethanethiol, propionic acid, and hexane (P < 0.05). Concentrations of diacetyl, acetoin, propionic acid, and hexane in litter were higher from low CP group compared to all other treatments on d 35 (P < 0.05) but not on d 15 and 29. A high litter moisture increased water activity (P < 0.01) and favored the emissions of methyl mercaptan, hydrogen sulfide, dimethyl sulfide, ammonia, trimethyl amine, phenol, indole, and 3-methylindole over others. Thus, the low CP diet, Bacillus subtilis based probiotic and the blend of Yucca/Quillaja saponin were effective in reducing the emissions of some key odorants from meat chicken litter

Altering broiler gut development, morphology, microbiology and function by manipulating feed grain type, particle size and milling method affects life-long performance

The modern broiler chicken increases its bodyweight by 5000% in the first six weeks of life. Even so, the genetic potential of the bird is ever increasing. The intensive nature of the modern broiler meat production system also potentially increases risk of transmissible diseases. Thus, the stresses on the bird's physiological systems; skeletal/muscular, digestive, immune and cardiovascular, are also increasing. Augmentation of suitable husbandry practices with appropriate nutrition will allow improved broiler production and health, by helping the birds’ physiological systems serve their respective intended purposes. That is, nutritionists need to present a feed to the broiler that more accurately meets its needs, not only on a nutritional level, but also on a physiological level, such that the bird is more able to effectively digest and absorb the feed due to improved physiological responses to the feed itself. The nutritionist can only do so much when it comes to feeding for profit. Aside from the nutritional needs of the bird, economic constraint is the largest factor that must be considered when formulating a broiler diet. It is therefore important that feed production costs are reduced, and at the other end, feed efficiency is improved, essentially enabling a more profitable product per unit cost of feed

Functional Interactions of Mannooligosaccharides with Dietary Threonine on Chicken Gastrointestinal Tract

This thesis presents a literature review and reports on four experiments conducted to investigate the interactive effects of MOS (Bio-MOS®, Alltech Biotechnology) with dietary threonine on the growth performance of broiler chickens. To elucidate the mechanisms underlying these effects, a series of other physiological responses in relation to the intestinal mucin dynamics, gut development, gut microflora, nutrient utilisation, and feed passage rate were examined

Necrotic enteritis challenge and high dietary sodium level affect odorant composition or emission from broilers

Necrotic enteritis (NE) challenge and high dietary sodium (from sodium chloride) level on odor flux from broiler litter was investigated using 160 day-old Ross 308 male chicks randomly assigned to 4 dietary treatments with 4 replicates of 10 birds each. A 2 × 2 factorial arrangement of treatments was employed. Factors were: presence or absence of NE challenge and normal (1.6 g/kg) or high (4.0 g/kg) dietary sodium (Na) level. On d 20, odorants were collected from litter headspace with a flux hood and measured using selected ion flow tube mass spectrometry (SIFT-MS). On d 33, while challenge did not lead to higher mortality, it reduced feed intake by 5.48% (P P P P P P P P P = 0.05), butyric acid (P P P = 0.07), carbon disulfide (P = 0.09), indole (P = 0.10), and formic acid (P = 0.10) compared to the unchallenged group. The birds fed a high Na diet produced higher litter moisture (P P P P P P P P P

Peroxisome proliferator-activated receptor gamma (PPARγ) upregulation and dietary fat levels in laying hens

The present study was conducted to investigate the effect of feeding the different levels of the dietary fat on the expression of genes encoding proteins involving energy metabolism, oxidative phosphorylation, and lipid synthesis including peroxisome proliferator-activated receptor gamma (PPARγ) of laying hens in the intestine. Birds fed diets with 3 levels of fat, that is, low (LF), medium (MF), and high fat (HF) were reared from 22 to 42 wk of age. Jejunum tissue was collected at week 42 for gene expression analysis. Dietary fat content as ether extract, net energy to AME ratio, and CP content of 3 treatment groups were as follows: LF: 25, 0.735, 187 (g/kg, DM); MF: 61, 0.739, 185 (g/kg, DM); HF: 73, 0.752, 181 (g/kg, DM). The BW, fat pad weight (g), fat pad–to–BW ratio (%) was the same for all the treatments (P &gt; 0·05). Birds fed a diet containing HF increased the AME daily intake per metabolic BW (BW0.75) ( 0·05). Birds fed a diet containing HF increased the AME daily intake per metabolic BW (BW0.75) (P P P &gt; 0·05). The mitochondrial count per cell showed no difference among the 3 groups with different dietary treatments ( 0·05). The mitochondrial count per cell showed no difference among the 3 groups with different dietary treatments (P &gt; 0·05). The results suggest that PPARγ may be important to the energy expenditure during nutrient absorption, digestion, and metabolism, and respiratory chain complexes, and other genes involving mitochondrial energy metabolism and lipogenesis may be less responsive to dietary treatment. 0·05). The results suggest that PPARγ may be important to the energy expenditure during nutrient absorption, digestion, and metabolism, and respiratory chain complexes, and other genes involving mitochondrial energy metabolism and lipogenesis may be less responsive to dietary treatment

A lytic bacteriophage isolate reduced Clostridium perfringens induced lesions in necrotic enteritis challenged broilers

Background Bacteriophages are viral predators of bacteria and are common in nature. Their host-specific infections against specific bacteria make them an attractive natural agent to control bacterial pathogens. Interest in the potential of bacteriophages as antibacterial agents in the production animal industries has increased. Methods A total of 18 bacteriophages were isolated from Australian commercial poultry environments, from which three highly active phages were chosen for enrichment. Sequencing libraries were prepared using a Nextera XT kit (Illumina) and sequenced on an Illumina MiSeq instrument using 2 × 300 bp paired-end chemistry. The sequence data were then assembled and aligned with a2 bacteriophage as the reference. An animal trial was performed by oral gavaging Clostridium perfringens netB containing strain EHE-NE18 to the Ross 308 broiler chickens prior inoculation with Eimeria species. The chickens were raised following the management guide for Ross 308 from d 0 to d 21 and fed with starter and grower diets met the specific breed nutrient requirements. Body weight gain and feed intake were measured on d 9 and d 21 and FCR adjusted with mortality was calculated. Results The isolated bacteriophages only had only 96.7% similarity to the most closely related, previously characterized, Clostridium bacteriophage indicated that they might represent a novel strain of bacteriophage. A “cocktail” containing the three bacteriophages was capable of lysing four known disease-inducing C. perfringens strains in vitro. Oral administration of the bacteriophages cocktail to broilers challenged with necrotic enteritis markedly alleviated intestinal necrotic lesions in the duodenum and jejunum on day 16 post-hatch. The phage treatment significantly reduced the lesion scores of birds challenged with NE (P 0.05). However, no effect on the growth performance was observed during the recorded period of days 9-21. Conclusion These findings suggest that bacteriophage treatment is a promising approach to protect intestinal health from C. perfringens induced necrotic enteritis. Further research will be required on the dosing, route of administration, and large scale validation studies to further advance this approach to pathogen control

Differential expression of intestinal genes in necrotic enteritis challenged broiler chickens with 2 different Clostridium perfringens strains

The primary cause of necrotic enteritis (NE) disease in chickens is the NetB-positive Clostridium perfringens bacterium. Many factors are known to affect the severity of NE in the challenge models of broiler chickens, and one of these factors is the virulence of C. perfringens strain. This study was conducted to evaluate the effect of 2 pathogenic C. perfringens strains in a NE challenge model on gut health and mRNA expression of genes encoding apoptosis, tight junction, immunity, and nutrient transporters in broilers. Day-old Ross-308 male broilers (n = 468) were allocated in a 2 × 3 factorial arrangement of treatments with in-feed antibiotics (no or yes) and challenge (Non, C. perfringens strain NE18, and C. perfringens strain NE36) as the factors. The birds in the challenged groups were inoculated with Eimeria species on day 9 and with a fresh suspension of C. perfringens NE18 or NE36 on day 14 and 15. Sample collection was performed on 2 birds of each pen on day 16. Necrotic enteritis challenge, impaired feed conversion ratio during day 0 to 16 compared with the control group where the effect of the NE36 challenge was more severe than that with NE18 (P P P P P P P C. perfringens strains can affect the severity of the disease through modulating the expression of intestinal genes encoding proteins responsible for apoptosis, gut integrity, immunity, mucus production, and nutrient transporters

Modulations of genes related to gut integrity, apoptosis, and immunity underlie the beneficial effects of Bacillus amyloliquefaciens CECT 5940 in broilers fed diets with different protein levels in a necrotic enteritis challenge model

Background: The ban of in-feed antimicrobial additives has negatively affected the poultry industry by causing necrotic enteritis (NE) to emerge in the flocks. Alternatives such as Bacillus probiotics have shown to be effective on eliminating the negative effects of this disease. Two experiments were conducted to investigate the effect of Bacillus amyloliquefaciens CECT 5940 (BA) in broiler chickens under NE challenge and/or fed diets with different protein levels. Methods: In both experiments, 480 day-old mix-sexed Ross-308 broilers were arranged in a 2 × 2 factorial arrangement of treatments. In experiment 1, the factors were NE challenge (yes or no) and probiotic (yes or no). In experiment 2, the factors were dietary crude protein levels (standard or reduced) and probiotic (yes or no) and were used under NE challenge condition. Oral administration of Eimeria oocysts (day 9) followed by inoculation with Clostridium perfringens (day 14 and 15) was used to induce NE challenge. On day 16, two birds from each treatment were gavaged with fluorescein isothiocyanate-dextran (FITC-d) and blood samples were collected for gut integrity evaluation, and jejunal samples were collected for gene expression assay. Results: In experiment 1, BA supplementation decreased caspase-3 (CASP3) (P CASP8) (P OCLD) (P IFN-γ) expression (P IgG) (P IgM) (P MUC2) (P TJP1) (P OCLD (P INF-γ (P IgA) (P IgM (P IgG (P  Conclusion: These findings suggest that supplementation of BA in broiler diets can improve gut health by modulation of genes related to the mucosal barrier, tight junction, and immunity in broilers challenged by unfavourable conditions such as NE challenge