Supplementation of broiler chicken diets with bovine lactoferrin improves growth performance, histological parameters of jejunum and immune-related gene expression

The aim of this study was to investigate the influence of dietary supplementation of bovine lactoferrin (bLF) on growth performance, carcass traits, histomorphology of jejunum, immune function and hepatic and splenic gene expression of interferon-gamma (IFN-γ) and interleukine-2 (IL-2) in broiler chickens. A total of 240 one-day-old Ross 308 male broiler chickens were randomly allotted into six dietary treatments with four replicate pens (10 chicks per pen) and fed experimental diet in 3 feeding phases (starter: d 0-10, grower: d 11-24 and finisher: d 25-42). The experimental treatments were (1) corn-soya bean meal-based basal diet (control), (2-5) basal diet supplemented with 200, 400, 600, 800 mg/kg bLF, respectively, and (6) basal diet supplemented with 200 mg/kg oxytetracycline (OTC). The average body weight gain (ABWG) of broilers fed 800 mg/kg bLF was 8.48% higher than those fed a corn-soybean meal-based diet during the starter period (d 0-10) (linear effect, p = 0.002; quadratic effect, p = 0.24). Average daily feed intake (ADFI) and the feed conversion ratio (FCR) were not affected (p>0.05) by bLF supplementation. At 42 days of age, the breast meat percentage and carcass yield of broilers fed 800 mg/kg bLF compared with the control group significantly increased by 9.51% and 6.03% respectively (p < 0.05). Compared with the chicks fed the control diet, the chicks fed diets supplemented with bLF had higher villus height, muscle thickness and villus surface area (p > 0.05). Dietary bLF inclusion increased the total immunoglobulin (IgT) titre against sheep red blood cells (SRBCs) antigen (linear effect, p = 0.031; quadratic effect, p = 0.035) and improved the phytohaemagglutinin-P (PHA-P)-skin test of broilers. Compared with the control, bLF enhanced the gene expression of IFN-γ in spleen (p = 0.048, linear effect, p = 0.009; quadratic effect, p = 0.093) and liver (p = 0.012, linear effect, p = 0.008; quadratic effect, p = 0.01) and IL-2 expression in spleen (p = 0.021, linear effect, p = 0.026; quadratic effect, p = 0.103). The bLF supplementation had no effect on IL-2 gene expression in liver (p > 0.05, linear effect, p = 0.213; quadratic effect, p = 0.159). In conclusion, we found that supplementation of broiler diets with 800 mg/kg bLF can improve the growth performance, carcass yield, cell-mediated and antibody-mediated immune responses and enhance the IL-2 and IFN-γ gene expression of broilers.

Role of diet-microbiota interactions in precision nutrition of the chicken: facts, gaps, and new concepts

In the intestine, host-derived factors are genetically hardwired and difficult to modulate. However, the intestinal microbiome is more plastic and can be readily modulated by dietary factors. Further, it is becoming more apparent that the microbiome can potentially impact poultry physiology by participating in digestion, the absorption of nutrients, shaping of the mucosal immune response, energy homeostasis, and the synthesis or modulation of several potential bioactive metabolites. These activities are dependent on the quantity and quality of the microbiota alongside its metabolic potential, which are dictated in large part by diet. Thus, diet-induced microbiota alterations may be harnessed to induce changes in host physiology, including disease development and progression. In this regard, the gut microbiome is malleable and renders the gut microbiome a candidate 'organ' for the possibility of precision nutrition to induce precision microbiomics-the use of the gut microbiome as a biomarker to predict responsiveness to specific dietary constituents to generate precision diets and interventions for optimal poultry performance and health. However, it is vital to identify the causal relationships and mechanisms by which dietary components and additives affect the gut microbiome which then ultimately influence avian physiology. Further, an improved understanding of the spatial and functional relationships between the different sections of the avian gut and their regional microbiota will provide a better understanding of the role of the diet in regulating the intestinal microbiome.

Nutrition, feeding and laying hen welfare

The relationship between nutrition and welfare is usually considered to be a direct result of supplying the hen with adequate quantities of feed and water. This simple notion of freedom from hunger and thirst belies the fact that nutrients play a pivotal role in the body’s response to challenges whether they relate to ambient temperature, gastrointestinal health, pathogen exposure, metabolic disorders, or social and mental stress. In all instances, maintaining homeostasis and allowing for physiologic response is dependent on an adequate and balanced nutrient supply. It is accepted that most laying hens are fed a complete diet, formulated commercially to provide the required nutrients for optimal health, egg production and welfare. In other words, the laying hen, irrespective of her housing, does not experience hunger or thirst. However, despite adequate nutrient and water supply, certain senarios can significantly affect and alter the nutrient requirements of the hen. Furthermore, the chemical composition and also the physical form of feed can significantly contribute to prevent or treat welfare and health conditions and is, therefore, a highly relevant tool to ensure and maintain an adequate welfare status. Therefore, this review takes a broader perspective of nutritional welfare and considers the nutrition of hens managed in different production systems in relation to nutritional physiology, gut microbiota, stress, metabolic disorders and feeding management.

Effects of a probiotic on the growth performance, intestinal flora, and immune function of chicks infected with Salmonella pullorum

This study investigated the effects of a Lactobacillus paracasei KL1 and Lactobacillus plantarum subsp. plantarum Zhang-LL mixed probiotic on Salmonella-caused pullorosis in chicks. A total of 120 1-day-old Nongda no.3 dwarf chicks were randomly assigned to 4 treatments, with 6 replicates of 5 birds each. The treatments were blank group, Salmonella pullorum-infected group, probiotic treatment group, and probiotic prevention (PP) group. All birds (n = 90) except those in the blank group were infected with S. pullorum on day 4. On day 14, the BW, ADG, mortality, pathology of tissue, cecum colony count, immune organ indices, cecal mucosa secretory IgA, and cytokines were investigated. The results showed that the chicks infected with S. pullorum were depressed and their BW reduced. The PP group had the highest ADG and lowest mortality rate (0%), whereas the S. pullorum-infected group had 37.50% mortality rate and lowest ADG. Pathologic sections showed that the probiotic treatment group had minor lesions but the PP group had no lesions in the ileum, cecum, and liver. Cecal Lactobacillus counts was the highest (P < 0.05) and Salmonella and Escherichia coli counts were the lowest (P < 0.05) in the PP group; Compared with the S. pullorum-infected group, the thymus and spleen indexes of the probiotic treatment group increased (P < 0.05), but they were unaffected (P > 0.05) in the bursa of Fabricius, whereas in the PP group, all the immune organs were increased (P < 0.05).Cecal mucosa secretory IgA and IL-4 were the highest (P < 0.05) and tumor necrosis factor α and interferon gamma were the lowest (P < 0.05) in the PP group; In summary, the Lactobacillus KL1 and L. plantarum Zhang-LL mixed probiotic effectively reduced the mortality of pullorosis in chicks, promoted the growth performance, regulated the balance of the intestinal flora, improved the immune function, resisted pullorosis disease, completely prevented chicks from pullorosis after infection, and reduced economy loss in the poultry industry.

Effect of Carotenoids, Oligosaccharides and Anthocyanins on Growth Performance, Immunological Parameters and Intestinal Morphology in Broiler Chickens Challenged with Escherichia coli Lipopolysaccharide

This study was conducted to investigate the effect of carotenoid, oligosaccharide and anthocyanin supplementation in broiler diets under Escherichia coli lipopolysaccharide (LPS) challenge. Ross 308 chickens were fed 5 diets: basal diet (control diet), diet supplemented with β-glucan in 0.05% (positive control) and diets with 0.5% carotenoid-, oligosaccharide- or anthocyanin contents. On the 26th days of age, chickens were challenged intraperitoneally 2 mg LPS per kg of body weight. 12 h after injection, birds were euthanized, then spleen and ileum samples were collected. LPS induced increased relative mRNA expression of splenic (p = 0.0445) and ileal (p = 0.0435) interleukin-1β (IL-1β), which was lower in the spleen in carotenoid (p = 0.0114), oligosaccharide (p = 0.0497) and anthocyanin (p = 0.0303)-treated chickens compared to LPS-injected control birds. Dietary supplementation of carotenoids also decreased relative gene expression of splenic interleukin-6 (IL-6) (p = 0.0325). In the ileum, β-glucan supplementation showed lower relative mRNA expression of toll-like receptor 5 (TLR-5) (p = 0.0387) compared to anthocyanin treatment. Gene expression of both splenic and ileal interferon-α (IFN-α), interferon-γ (IFN-γ), toll-like receptor 4 (TLR-4) and toll-like receptor 5 (TLR-5) were not influenced by dietary supplements. In conclusion, carotenoids, oligosaccharides and anthocyanins could partially mitigate the immune stress caused by LPS challenge. All of the compounds impacted longer villus height (p < 0.0001), villus height:crypt depth ratios were higher after β-glucan (p < 0.0001) and anthocyanin (p = 0.0063) supplementations and thickened mucosa was observed in β-glucan (p < 0.0001), oligosaccharide (p < 0.0001) and anthocyanin (p = 0.048) treatments. All of these findings could represent a more effective absorption of nutrients.