Modulation of immune function by conjugated linoleic acid in chickens

Cellular and humoral immunity of broilers subjected to posthatch fasting and a prestarter diet containing conjugated linoleic acid

This study aimed to evaluate the immunity of chickens up to 35 d subjected to posthatch fasting and supplementation with conjugated linoleic acid (CLA). A total of 320 chicks were housed in a completely randomized design with a 2 × 2 factorial arrangement (0 or 12 h of fasting × 0.000 or 0.025% CLA in a prestarter diet), totaling 4 treatments (No-F-12 h; F-12 h; No-CLA; CLA) with 8 replicates of 10 birds each. The relative weights (% body weight) of the spleen and bursa were determined 12 h posthatch (Post-12 h) and then weekly. Immunoglobulin Y (IgY) titers against Newcastle disease virus (NDV) were measured by ELISA in the yolk sac contents Post-12 h and in the serum weekly. Hypersensitivity to phytohemagglutinin (PHA) inoculation was evaluated by toe-web swelling response on d 13 and 34, 4 times a day (after 3 h, 6 h, 12 h, and 24 h inoculation, respectively, PHA-3 h, PHA-6 h, PHA-12 h, and PHA-24 h). The data were subjected to analysis of variance (P < 0.05). F-12h reduced the Post-12 h relative weight of the spleen, and CLA reduced the relative weight of the bursa at this stage and at 28 d. At 13 d, F-12 h reduced PHA-3 h, whereas PHA-12 h was increased by CLA. At 34 d, CLA reduced PHA-3 h. A greater reaction was observed in the No-F-12 h-CLA chicks, for the PHA-24 h. In the Post-12 h evaluation, F-12h reduced, whereas CLA increased NDV-specific IgY titers in the yolk sac. No-F-12 h-No-CLA chicks had the lowest serum titers. At 21 d, F-12 h-CLA chicks exhibited the highest serum titers. Titers were higher in the F-12 h-No-CLA chicks, when compared to other treatments. At 28 d, fasting reduced the titers. In conclusion, F-12 h and CLA accelerated the transfer of immunoglobulins from the yolk sac to the serum. F-12 h impairs cellular immunity, whereas CLA favors it.

Potential role of important nutraceuticals in poultry performance and health - A comprehensive review

Antibiotics use in poultry as a growth promoter leads to the propagation of antibiotic-resistant microorganisms and incorporation of drug residues in foods; therefore, it has been restricted in different countries. There is a global trend to limit the use of antibiotics in the animal products. Prevention of the antibiotics use in the poultry diets led to the reduction in the growth performance. Consequently, there is a high demand for natural substances that lead to the same growth enhancement and beneficially affect poultry health. These constituents play essential roles in regulating the normal physiological functions of animals including the protection from infectious ailments. Nutraceuticals administration resulted beneficial in both infectious and noninfectious diseases. Being the natural components of diet, they are compatible with it and do not pose risks associated with antibiotics or other drugs. Nutraceuticals are categorized as commercial additives obtained from natural products as an alternative feed supplement for the improvement of animal welfare. This group includes enzymes, synbiotics, phytobiotics, organic acids and polyunsaturated fatty acids. In the present review, the summary of various bioactive ingredients that act as nutraceuticals and their mode of action in growth promotion and elevation of the immune system has been presented.

Modulatory Effect of Linoleic Acid During Brucella abortus 544 Infection in Murine Macrophage RAW264.7 Cells and Murine Model BALB/c Mice

In this study, we investigated the effects of linoleic acid (LA) treatment on Brucella abortus infection in professional phagocyte RAW264.7 cells, particularly during the pathogens invasion and intracellular growth in these cells, as well as in murine model BALB/c mice focusing on bacterial splenic proliferation and immunoregulatory activities. LA inhibited the growth of Brucella in a doseand time-dependent manner. The ability of the pathogen to enter the phagocytes was inhibited as was its survival within these cells. This was accompanied by increased nitrite accumulation in these cells at 24 h post-infection. The concentration of LA used in the present study did not affect the total body weight or liver function of the mice. During Brucella infection, the total splenic weight of these animals was not changed; rather, resistance to bacterial proliferation was enhanced in the spleen. Furthermore, mice treated with LA displayed elevated levels of IL-12 and IFN-γ but reduced levels of IL-10 during infection. The findings in this study showed the regulatory role of LA against B. abortus infection suggesting its potential use in designing intervention strategy for brucellosis.

Maternal supplementation with fish oil modulates inflammation-related MicroRNAs and genes in suckling lambs

Dietary n-3 long-chain fatty acids (n-3 LCFA) have been shown to modify lipid metabolism and immune function. The objective of this study was to evaluate the effect of periparturient fish oil (FO) supplementation on the inflammation and metabolic health of ewes and their lambs at a molecular level. Prepartum ewes were fed control diet (CON, n = 12) or CON supplemented with 2% DM of calcium soap of FO (n = 12) from 28 days before until 21 days after parturition. The ewes were evaluated for plasma metabolites and milk composition. The experiment was followed by analyzing the relative transcript abundance of circulating microRNAs (miRNAs) in plasma and targeted miRNA/mRNA expression in peripheral blood mononuclear cells (PBMCs) in both ewes and lambs. FO treatment decreased prepartum feed intake (1812 ± 35 vs 1674 ± 33 g/day, P < 0.01), whereas the influence on plasma metabolites was negligible. Dietary FO supplementation decreased milk fat percentage (8.82 ± 0.49 vs 7.03 ± 0.45, P = 0.02) and reduced milk n-6/n-3 (P < 0.05). Also, it altered the expression of plasma-circulating miRNAs in both ewe and lamb (P < 0.05). Furthermore, maternal nutrition of FO downregulated the relative expression of miR-33a and miR-146b and transcript abundance of genes IL-1β (0.41-fold) and NF-κB (0.25-fold) in lambs' PBMC. In conclusion, results showed that FO supplementation starting antepartum affects milk composition and circulating miRNA in dams and the inflammatory markers in lambs delivered by the supplemented ewes. These may provide a strategy to maintain immune balance during gestation and develop the immune system in lambs.

Managing gut health without reliance on antimicrobials in poultry

It is well established that antimicrobials in animal feed enhance feed efficiency, promote animal growth and improve the quality of animal products. However, resistance development in bacterial populations, and hence consumer demand for products free of antimicrobial residues, has prompted efforts to develop alternatives that can replace antimicrobials without causing loss of productivity or product quality. One of the key barriers to complete withdrawal from antimicrobial use is microbial infection, for example, necrotic enteritis. There is much interest in using in-feed nutraceuticals such as prebiotics, probiotics, organic acids and plant extracts as alternatives to antimicrobials to create a healthy gastrointestinal environment and to prevent and treat enteric infections. Enzymes are generally used to alleviate anti-nutritional factors in feed, but there is growing awareness of their beneficial effects on the gastrointestinal environment, and consequently on gut health. An example of this is production of prebiotic xylo-oligosaccharides when xylanase is added to feed. This review discusses developments in alternatives to antimicrobials that can aid in managing gut health in a post-antimicrobial era, with particular reference to recent nutritional strategies.

Effects of conjugated linoleic acid and lutein on the growth performance and immune response of broiler chickens

The effects of lutein and conjugated linoleic acid (CLA) on growth performance and immune response of broiler chickens were evaluated in the presence and absence of Salmonella lipopolysaccharide (LPS) immune challenge. Cobb chicks (360; 1 to 22 d of age) were used in a 3 × 2 factorial arrangement of CLA (0, 1, and 2%) and lutein (0 and 50 mg/kg) dietary levels. At d 8 and 15, birds were injected with BSA to assess IgY production. At d 20, birds were injected with LPS. Samples of liver, spleen, and duodenum were collected at 3 and 16 h post-LPS challenge for RT-qPCR analysis of RXRα, RXRγ, PPARα, PPARγ, TLR-4, IL-1β, IL-2, IL-10, and IL-12 gene expression. CLA decreased BW, BW gain (BWG), and G:F from d 1 to 20, but these effects were reversed when lutein was included in the 1% CLA diet (P < 0.001). The production of IgY anti-BSA increased following a 2% CLA supplementation (P < 0.01). LPS increased the liver:BW ratio at 3 h post-injection (P < 0.001) and decreased BWG at 3, 16, and 40 h (P < 0.001). Lutein decreased plasmatic nitric oxide levels (P < 0.01). LPS downregulated PPARα mRNA in the duodenum (P = 0.02) and liver (P = 0.04), and PPARγ (P = 0.01) and RXRα (P = 0.08) in the spleen; these effects were not reversed by CLA or lutein as initially hypothesized. Although LPS upregulated IL-1β (P = 0.02) and IL-12 (P = 0.07) expression, lutein downregulated these pro-inflammatory cytokines in the liver (P = 0.03 and P = 0.07, respectively). Lutein decreased splenic (P = 0.09) but increased hepatic (P = 0.06) TLR-4 mRNA. A dietary CLA supplementation of 2% increased hepatic RXRα (P = 0.10). In conclusion, CLA decreased broiler chicken growth performance, but lutein could prevent this negative effect (depending on CLA dose). Lutein had an anti-inflammatory effect, and a 2% CLA supplementation improved the humoral immune response.