Abstract
The gastrointestinal tract is considered as one of the main target organs affected by heat stress. Phytogenic feed additives containing phenolics and flavonoids can improve the resistance of ...broilers to heat stress. This study was conducted to investigate the effects of dietary supplementation with enzymatically treated Artemisia annua (EA) on growth performance, intestinal morphology, digestive enzyme activities, immunity and antioxidant capacity of broilers challenged with heat stress. One hundred and forty-four 21-day-old male Arbor Acres broilers were randomly distributed into 3 treatments: 1) non-challenged control (CON); 2) heat-stress-challenged control (HS); and 3) heat-stress-challenged group + 1 g EA/kg diet (HS-EA). From 22 to 41 d, broilers in the CON group were housed at 22 ± 1°C, the HS and HS-EA groups, in which broilers were raised at 34 ± 1°C for 8 h (0900-1700 h) and the temperature for the rest time was the same as that of the CON group. The EA supplementation alleviated the compromised body weight gain and intestinal morphology impairment caused by heat stress challenge (P < 0.05). The EA attenuated heat-stress-induced decreased intestinal lipase, trypsin and total superoxide dismutase activities, and reduced intestinal secretory immunoglobulin A (SIgA) and IgG concentrations (P < 0.05). The EA inclusion prevented the elevation of intestinal malondialdehyde content and reduction of intestinal glutathione concentration induced by heat stress challenge (P < 0.05). The intestinal mRNA abundances of nuclear factor erythroid 2-related factor 2, heme oxygenase 1, glutathione peroxidase, gamma-glutamyl cysteine ligase larger catalytic subunit and gamma-glutamyl cysteine ligase smaller modulator subunit in heat-stressed broilers were increased in response to dietary EA treatment (P < 0.05). In conclusion, dietary supplementation of 1 g/kg EA could alleviate heat-stress-induced compromised growth performance and intestinal damage of broilers.
Nucleotide-rich yeast extract (YN) was investigated for effects on growth performance, jejunal physiology, and cecal microbial activity in Eimeria-challenged broiler chickens. A total of 360-day-old ...male chicks (Ross × Ross 708) were placed on floor pens and provided a corn-soybean meal-based diet without or with YN (500 g/MT; n = 12). On d 10, 6 replicates per diet were orally administered with 1 mL of E. acervulina and E. maxima sporulated oocysts and the rest (non-challenged control) were administered with 1 mL of distilled water. On d 15, 5 birds/pen were then necropsied for intestinal lesion scores, histomorphology and cecal digesta pH, short chain fatty acids (SCFA), and microbial community using Illumina Miseq platform. Supplemental YN improved (P = 0.01) Feed conversion ratio (FCR) during the prechallenge phase (d 0 to 10). In the postchallenge period (d 11 to 15), Eimeria depressed (P < 0.05) Body weight gain (BWG) relative to non-challenged birds, whereas YN-fed birds had a higher (P = 0.05) BWG compared to that of non-YN-fed birds. There was an interaction between YN and Eimeria on jejunal villi height (VH) (P = 0.001) and expression of cationic amino acid transporter 1(CAT1) (P = 0.04). Specifically, in the absence of Eimeria, YN-fed birds had a shorter VH (892 vs. 1,020 μm) relative to that of control but longer VH (533 vs. 447 μm) in the presence of Eimeria. With respect to CAT1, YN-fed birds had a higher (1.65 vs. 0.78) expression when subjected to Eimeria than when not challenged. Independently, Eimeria decreased (P < 0.01) the jejunal expression of maltase, Na glucose transporter 1 and occludin genes, ceca digesta abundance of genus Clostridium cluster XlVa and Oscillibacter but increased (P < 0.01) jejunal proliferating cell nuclear antigen and interleukin 10. Interaction between YN and Eimeria was observed for ceca digesta pH (P = 0.04) and total SCFA (P = 0.01) such that YN increased SCFA in the absence of Eimeria but reduced SCFA and increased pH in the presence of Eimeria. In summary, Eimeria impaired performance and gut function and shifted gut microbiome; YN improved performance independently, attenuated Eimeria damage on indices of gut function, and modulated cecal microbiome.
The intense genetic selection for rapid growth in broilers has resulted in an increase in voluntary feed intake and growth rate, accompanied by increased fat deposition in adipose tissue depots ...throughout the body. Adipose tissue expansion is a result of the formation of adipocytes (several processes collectively referred to as adipogenesis) and cellular accumulation of triacylglycerols inside lipid droplets. In mammals, different anatomical depots are metabolically distinct. The molecular and cellular mechanisms underlying adipose tissue development have been characterized in mammalian models, whereas information in avian species is scarce. The purpose of this review is to describe factors regulating adipogenesis in chickens, with an emphasis on dietary factors and the broiler. Results from many studies have demonstrated effects of dietary nutrient composition on adipose tissue development and lipid metabolism. Transcription factors, such as peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding proteins α and β, and sterol regulatory element binding proteins orchestrate a series of cellular events that lead to an increase in activity of fatty acid transport proteins and enzymes that are responsible for triacylglycerol synthesis. Understanding the mechanisms underlying adipose tissue development may provide a practical strategy to affect body composition of the commercial broiler while providing insights on diets that maximize conversion into muscle rather than fat and affect depot-dependent deposition of lipids. Because of the propensity to overeat and become obese, the broiler chicken also represents an attractive biomedical model for eating disorders and obesity in humans.
The transition to using dual-purpose chickens is an alternative to killing male hatchlings of high performance egg-laying chickens. This study aimed to compare the gastrointestinal tract of a ...recently developed genetic line of dual purpose male chicken, Lohmann Dual (LD), with that of a broiler line, Ross 308. Eighty birds from each line were grown until they reached an average body weight 2000 g (5 weeks for Ross and 9 for LD birds). Six birds of each line were sampled weekly. Body weight (BW), normalized mass of gastrointestinal segments and relative length of intestine were determined. Histologically the villus height, epithelium height, crypt depth, mucosal enlargement factor and the tunica muscularis thickness were measured in jejunum and ileum. Data were regressed against body weight and genetic line. Jejunal enterocyte microvilli and junctional complexes length were measured. Normalized mass and relative length of the gastrointestinal segments were greater in LD birds than in Ross birds at all ages. After day 7 these decreased steadily over the lifetime of the birds in both genetic lines. The growth curves of the gastrointestinal segments of the LD birds were similar to those of the Ross birds. In birds of the same BW, LD birds had a significantly heavier gizzard, shorter intestine, higher jejunal villi, thicker ileal tunica muscularis and smaller ileal mucosal enlargement factor than were found in Ross birds. The large gizzard in LD chickens presumably increases the degree of food processing and enhances availability of nutrients in the orad part of the intestine leading to a lower nutrient concentration and a smaller absorption surface area in the ileum of the LD compared to the Ross chickens. The anatomical differences between the two lines are important criteria for further selection and should be considered in their feeding management.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Host genetic makeup plays a role in early gut microbial colonization and immune programming. Interactions between gut microbiota and host cells of the mucosal layer are of paramount importance for a ...proper development of host defence mechanisms. For different livestock species, it has already been shown that particular genotypes have increased susceptibilities towards disease causing pathogens. The objective of this study was to investigate the impact of genotypic variation on both early microbial colonization of the gut and functional development of intestinal tissue. From two genetically diverse chicken lines intestinal content samples were taken for microbiota analyses and intestinal tissue samples were extracted for gene expression analyses, both at three subsequent time-points (days 0, 4, and 16).
The microbiota composition was significantly different between lines on each time point. In contrast, no significant differences were observed regarding changes in the microbiota diversity between the two lines throughout this study. We also observed trends in the microbiota data at genus level when comparing lines X and Y. We observed that approximately 2000 genes showed different temporal gene expression patterns when comparing line X to line Y. Immunological related differences seem to be only present at day 0, because at day 4 and 16 similar gene expression is observed for these two lines. However, for genes involved in cell cycle related processes the data show higher expression over the whole course of time in line Y in comparison to line X.
These data suggest the genetic background influences colonization of gut microbiota after hatch in combination with the functional development of intestinal mucosal tissue, including the programming of the immune system. The results indicate that genetically different chicken lines have different coping mechanisms in early life to cope with the outside world.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The effects of different rearing systems (RS) including cage rearing systems (CRS), litter rearing systems (LRS), and perforated plastic slate rearing systems (PSRS) on the productive performance, ...carcass traits, blood hematological and biochemical parameters, and humoral immunity in broiler chickens exposed to heat stress were investigated. A total of 270 1-day-old Avian 48 chicks were randomly assigned to 3 groups equally, each was divided into 9 replicates (each of 10 birds) housed in studied RS. Results revealed that CRS had higher (P < 0.001) body weight and weight gain at all experimental periods (except in the sixth wk for weight gain) followed by LRS. Birds housed in PSRS consumed lower (P < 0.001) feed than those in CRS (during the fourth to sixth and overall periods) and LRS (during all experimental periods except the second one). Best values of feed conversion ratio and European broiler index were shown in CR birds. All carcass traits were not altered by different RS except the percentages of dressing, liver, breast, and left filet, which were elevated (P < 0.05) in caged birds. Eosinophil, lymphocyte, basophil, and monocyte counts and phagocytic index and activity were reduced (P < 0.05 or P < 0.01) in LRS. Humoral immune response against the Newcastle disease virus and avian influenza were not differed. Birds in LRS showed higher (P < 0.05) serum cholesterol, uric acid, and lactate dehydrogenase as well as liver and muscle cholesterol contents. Lipid peroxidation was reduced (P < 0.05) in the LRS and PSRS groups, whereas superoxide dismutase was elevated (P < 0.05) in CRS and LRS. Thus, CRS and LRS were preferred for better growth performance and carcass traits of heat-stressed broilers, whereas CRS and PSRS were better in reducing tissue cholesterol under the conditions of our study.
The current study investigated the efficacy of a probiotic mixture on ameliorating heat stress-induced impairment of intestinal microflora, morphology, and barrier integrity in broilers. The ...probiotic mixture contained Bacillus licheniformis, Bacillus subtilis, and Lactobacillus plantarum. Three hundred sixty 21-d-old Ross 308 male broilers were allocated in 4 experimental treatments, each of which was replicated 6 times with 15 broilers per replicate. A 2 × 2 factorial design was used in the study, and the main factors were composed of diet (basal diet or addition of 1.5 g/kg of probiotic mixture) and temperature (thermoneutral zone or heat stress). From d 22 to 42, birds were either raised in a thermoneutral zone (22°C) or subjected to cyclic heat stress by exposing them to 33°C for 10 h (from 0800 to 1800) and 22°C from 1800 to 0800. Compared with birds kept in the thermoneutral zone, birds subjected to heat stress had reduced ADG and ADFI; lower viable counts of Lactobacillus and Bifidobacterium and increased viable counts of coliforms and Clostridium in small intestinal contents; shorter jejunal villus height, deeper crypt depth, and lower ratio of villus height to crypt depth; decreased jejunal transepithelial electrical resistance and a higher level of jejunal paracellular permeability of fluorescein isothiocyanate dextran 4 kDa; and downregulated protein levels of occludin and zonula occludens-1 (P < 0.05). Supplemental probiotics increased (P < 0.05) small intestinal Lactobacillus and Bifidobacterium, jejunal villus height, protein level of occludin, and decreased (P < 0.05) feed to gain ratio and small intestinal coliforms. These results indicate that dietary addition of probiotic mixture was effective in partially ameliorating intestinal barrier function. But no temperature × diet interaction was observed in the present study, revealing that the supplemented probiotics had the same effect at both temperatures.
There is an increasing interest in free-range poultry with the increasing focus on food safety and animal welfare. This study was conducted to evaluate the effects of grazing mixed-grass pastures on ...growth performance, immune responses, and intestinal microbiota in free-range laying chickens. Ten-week-old female Beijing-you chickens were blocked by the BW and randomly assigned to 3 free-range systems in poplar plantations for 120 d: forage-removed paddocks with a high stocking density of 5 m2/hen (control CK); mixed-grass pastures with a low stocking density of 6 m2/hen ;or mixed-grass pastures with a high stocking density of 5 m2/hen. Intestinal microbial community analysis was performed by 16S rRNA gene sequencing using Illumina MiSeq. The results revealed that no differences (P > 0.05) were found between the 3 raising systems for the BW and ADG. Chickens grazing mixed-grass pastures exhibited decreased (P > 0.05) mortality and improved immune responses as evidenced by increased T-lymphocyte proliferation (P > 0.05) and immunoglobulin A (P > 0.05) and immunoglobulin M concentrations (P < 0.05) compared with those raised in forage-removed paddocks. Metagenomic analysis indicated that grazing mixed-grass pastures regulated the intestinal microbiota by increasing the prevalence of beneficial bacteria, such as Lactobacillus, Bacteroides, and Faecalibacterium, and reducing potentially pathogenic bacteria population, such as the Rikenellaceae_RC9_gut_group compared with the CK. Therefore, this study indicated that grazing mixed-grass pastures could positively influence intestinal microbiota that may contribute to the overall growth and immunity of free-range chickens and that a low stocking density of 6 m2/hen was optimal to Beijing-you chickens grazing mixed-grass pastures.
The present study was conducted to investigate growth performance, carcass characteristics, short-chain fatty acids, fatty acid composition in abdominal fat, and serum parameters in broiler chickens ...fed diets containing corn oil, coconut oil, or black soldier fly larvae (BSFL) oil at the level of 50 g per kg of diet during the 30-day-feeding period. A total 450 one-day-old male broiler chicks (Ross 308) were randomly allocated to one of 3 dietary groups. Each treatment had 10 replicates with 15 chicks per replicate. Feed conversion ratio was decreased in the coconut and BSFL oil group compared with the corn oil group. Dietary BSFL oil increased ileal weight-to-length ratio at day 30 after hatch. Dietary BSFL oil increased significantly ileal branched-chain fatty acid (P < 0.05) and moderately total short-chain fatty acid in 15-day-old broilers (P = 0.074). At day 30, ileal propionate was highest in the coconut oil group but cecal propionate was highest (P < 0.05) in the BSFL oil group. Fatty acid composition of abdominal fat was affected by dietary fat sources. Especially, chickens fed diets containing coconut oil or BSFL oil had higher contents (P < 0.05) of saturated fatty acid being dominant in lauric and myristic acids compared with those fed on corn oil. On the other hand, the reverse trend was noted (P < 0.05) as to polyunsaturated fatty acids being dominant in corn oil compared with coconut oil and BSFL oil. Coconut oil vs. corn oil significantly increased total and high-density lipoprotein cholesterol. Finally, BSFL oil vs. corn oil significantly increased total antioxidant capacity in chickens. It is concluded that dietary BSFL oil improves feed conversion ratio and increases the incorporation of medium-chain fatty acids into abdominal fat pad and serum antioxidant capacity in broiler chickens.
PDF
