Influence of dietary nicotinic acid supplementation on lipid metabolism and related gene expression in two distinct broiler breeds of female chickens

Developmental Changes of Duckling Liver and Isolation of Primary Hepatocytes

The liver is the main site of fat synthesis and plays an important role in the study of fat deposition in poultry. In this study, we investigated the developmental changes of duckling livers and isolated primary duck hepatocytes. Firstly, we observed morphological changes in duckling livers from the embryonic period to the first week after hatching. Liver weight increased with age. Hematoxylin-eosin and Oil Red O staining analyses showed that hepatic lipids increased gradually during the embryonic period and declined post-hatching. Liver samples were collected from 21-day-old duck embryos for hepatocyte isolation. The hepatocytes showed limited self-renewal and proliferative ability and were maintained in culture for up to 7 days. Typical parenchymal morphology, with a characteristic polygonal shape, appeared after two days of culture. Periodic acid-Schiff (PAS) staining analysis confirmed the characteristics of duck embryo hepatocytes. PCR analysis showed that these cells from duck embryos expressed the liver cell markers ALB and CD36. Immunohistochemical staining and immunofluorescence analysis also confirmed ALB and CK18 expression. Our findings provide a novel insight regarding in vitro cell culture and the characteristics of hepatocytes from avian species, which could enable further studies concerning specific research on duck lipid metabolism.

Cecum microbiome and metabolism characteristics of Silky Fowl and White Leghorn chicken in late laying stages

Cecal microflora plays a key role in the production performance and immune function of chickens. White Leghorn (WL) is a well-known commercial layer line chicken with high egg production rate. In contrast, Silky Fowl (SF), a Chinese native chicken variety, has a low egg production rate, but good immune performance. This study analyzed the composition of cecal microbiota, metabolism, and gene expression in intestinal tissue of these varieties and the correlations among them. Significant differences were observed in the cecal microbes: Bacteroides was significantly enriched in WL, whereas Veillonellaceae and Parabacteroides were significantly enriched in SF. Carbohydrate biosynthesis and metabolism pathways were significantly upregulated in WL cecum, which might provide more energy to the host, leading to persistently high levels of egg production. The higher Parabacteroides abundance in SF increased volicitin content, enhanced α-linolenic acid metabolism, and significantly negatively correlated with metabolites of propanoate metabolism and carbohydrate metabolism. Genes related to lipid metabolism, immunity, and melanogenesis were significantly upregulated in the SF cecum, regulating lipid metabolism, and participating in the immune response, while genes related to glucose metabolism and bile acid metabolism were expressed at higher levels in WL, benefiting energy support. This study provided a mechanism for intestinal microorganisms and metabolic pathways to regulate chicken egg-laying performance and immunity.

Effects of dietary nicotinic acid supplementation on meat quality, carcass characteristics, lipid metabolism, and tibia parameters of Wulong geese

The purpose of this study was to evaluate the effects of nicotinic acid (NA) supplementation on the meat quality, carcass characteristics, lipid metabolism, and tibia parameters in Wulong geese. A total of 360 twenty-nine-day-old Wulong geese were randomly divided into 6 treatments, and each treatment included 6 pens with 10 birds per pen. Birds were fed a basal diet supplemented with 0, 20, 40, 60, 80, or 100 mg/kg NA for 12 wk. Dietary NA supplementation linearly decreased L* value and increased pH and water-holding capacity in the breast muscle (P < 0.05). Increasing NA levels linearly and quadratically decreased shear force of breast muscle (P < 0.001). Dietary NA supplementation linearly reduced the thickness of subcutaneous fat plus the skin and percentage of abdominal fat, and enhanced the width of intermuscular fat band (P < 0.001). Dietary NA addition linearly and quadratically increased intramuscular fat (IMF) content (P ≤ 0.001). Increasing NA levels decreased serum total cholesterol and low-density lipoprotein cholesterol levels and increased serum lipase activity and hepatic mRNA expression of lipoprotein lipase in a linear manner (P < 0.05). There were linear and quadratic effects in serum triglycerides and high-density lipoprotein cholesterol (HDL-C) levels and malate dehydrogenase activity with the NA addition (P < 0.05). Feeding the NA-supplemented-diets linearly increased tibia length, circumference, fat-free dry weight, and ash content (P < 0.001). There were linear and quadratic increases in Ca and P contents with the NA supplementation (P < 0.05). According to the quadratic regression analyses fitted to shear force, IMF content, serum triglycerides and HDL-C levels, and tibial Ca and P contents, the optimal dietary NA supplementation was 80 to 90 mg/kg. In conclusion, NA addition enhanced meat quality and IMF content, regulated lipid metabolism, and increased tibia quality of Wulong geese. The dosage of 80 mg/kg NA in Wulong geese aged 5 to 16 wk was recommended.

Bacillus Subtilis 29784 as a Feed Additive for Broilers Shifts the Intestinal Microbial Composition and Supports the Production of Hypoxanthine and Nicotinic Acid

The probiotic Bacillus subtilis strain 29784 (Bs29784) has been shown to improve performance in broilers. In this study, we used a metabolomic and 16S rRNA gene sequencing approach to evaluate effects of Bs29874 in the broiler intestine. Nicotinic acid and hypoxanthine were key metabolites that were produced by the strain in vitro and were also found in vivo to be increased in small intestinal content of broilers fed Bs29784 as dietary additive. Both metabolites have well-described anti-inflammatory effects in the intestine. Furthermore, Bs29784 supplementation to the feed significantly altered the ileal microbiome of 13-day-old broilers, thereby increasing the abundance of genus Bacillus, while decreasing genera and OTUs belonging to the Lactobacillaceae and Enterobacteriacae families. Moreover, Bs29784 did not change the cecal microbial community structure, but specifically enriched members of the family Clostridiales VadinBB60, as well as the butyrate-producing families Ruminococcaceae and Lachnospiraceae. The abundance of various OTUs and genera belonging to these families was significantly associated with nicotinic acid levels in the cecum, suggesting a possible cross-feeding between B. subtilis strain 29784 and these beneficial microbes. Taken together, the data indicate that Bs29784 exerts its described probiotic effects through a combined action of its metabolites on both the host and its microbiome.

Effect of dietary niacin supplementation on performance, total tract nutrient retention, carcass yield and meat lipid profile of growing turkeys

A study was conducted to investigate the influence of dietary high or recommended nicotinic acid (niacin) supplementation on growth performance, total tract nutrient digestibility, hematology, serum chemistry, and lipoprotein concentrations in the serum and meat of growing turkeys. Turkeys were assigned to three treatments on weight equalisation basis with five replicates of eight turkeys in each group. Experimental diets were: no supplemental niacin (Control), a diet supplemented with 60 mg/kg niacin termed as recommended niacin supplementation and a diet supplemented with 180 mg/kg niacin termed as high niacin supplementation (HNS). The experiment lasted for the grower (Day 56–84) and finisher phases (Day 84–112) of the birds. Dietary inclusion of HNS increased (P &lt; 0.01) bodyweight gain, metabolisable energy (Days 84 and 112), dressing percentage and retail cut parts of turkeys (Day 112) in relation to the Control-fed turkeys. Furthermore, least white blood cell count and higher concentrations of packed cell volume, red blood cells and hemoglobin (P &lt; 0.01) were found in turkeys fed HNS on Days 84 and 112. Similarly, turkeys in the HNS group had improved serum constituents including serum protein, uric acid, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphate. The blood and meat lipid profile analysis showed that low density lipoprotein and total cholesterol were least (P &lt; 0.05) in turkeys fed HNS. Collectively, dietary high supplementation of niacin (180 mg/kg) improves production performances, reduces serum and meat fat content and improve indicators of stress resistance ability in growing turkeys.

Effect of Dietary Niacin Supplementation on Growth Performance, Nutrient Digestibility, Hematology, and Lipoprotein Concentrations of Young Turkeys, Meleagris gallopavo

The growth performance, nutrient digestibility, hematology, serum chemistry, and lipoprotein concentrations of turkey (Meleagris gallopavo) poults fed diets supplemented with high or recommended concentrations of niacin were investigated in this study. A total of 120 four-week-old turkey poults were randomly divided into three treatment groups with five replicates of eight birds in each group. The poult diets were supplemented with 0.0, 60, and 180 mg/kg niacin in the three treatments, termed control, recommended niacin supplementation (RNS), and high niacin supplementation (HNS), respectively. The study lasted for four weeks. The results showed that the HNS treatment reduced the feed intake and increased the body weight gain of poults. The apparent, nitrogen-corrected, and true metabolizable energy contents were the highest in the HNS-group turkey poults (P<0.05). The red and white blood cell counts and hemoglobin concentration of the turkeys improved with increasing niacin supplementation (P<0.01). The serum constituents, including the serum protein and globulin, were significantly increased (P<0.05), while the uric acid and creatinine contents were significantly reduced in the HNS-group turkeys. Similarly, the HNS-group turkeys exhibited significantly reduced alanine aminotransferase (ALT) and alkaline phosphatase (ALP) contents, while the RNS-group turkeys had the least aspartate aminotransferase (AST) content. In addition, the HNS-group turkeys had the least serum low-density lipoprotein (LDL), triglyceride, and total cholesterol concentrations and the highest serum high-density lipoprotein (HDL) (P<0.01) concentrations. In conclusion, the supplementation of 180 mg/kg niacin in the diet reduced the feed intake and serum ALT, ALP, LDL, triglyceride, and cholesterol contents and increased the body weight gain, metabolizable energy, and HDL concentration in turkeys. This study showed that niacin supplementation could reduce the fat content without compromising the body weight gain and increase stress resistance in turkey poults.

The role of cinnamon as a modulator of the expression of genes related to antioxidant activity and lipid metabolism of laying quails

Since cinnamon has vitamins and minerals in addition to antioxidants compounds in its chemical composition studies have shown the potential of cinnamon supplementation on some important characteristics in the performance of birds. Thus, this study was conducted under the hypothesis that the inclusion of cinnamon in the laying quail diet could influence the performance of the birds through the expression of genes related to antioxidant activity and lipid metabolism. To test this hypothesis, 144 Japanese quail (Coturnix japonica) with an initial age of 18 weeks and average weight of 133g were distributed in a completely randomized design with two treatments: no cinnamon supplementation (NCS—control group) and with supplementation of 9g/kg of cinnamon powder (CPS). The experiment lasted for 84 days. At the end of the experimental period, six animals from each treatment were euthanized by cervical dislocation, blood was collected and organs weighed. Liver tissue was collected for gene expression and biochemical analyses. We observed a significant effect of cinnamon inclusion on the weight of the pancreas (P = 0.0418), intestine (P = 0.0209) and ovary (P = 0.0389). Lower weights of the pancreas and intestine, and a higher ovary weight was observed in birds receiving the CPS diet. Quails fed with cinnamon supplementation also had better feed conversion per egg mass (2.426 g /g, P = 0.0126), and higher triglyceride (1516.60 mg/dL, P = 0.0207), uric acid (7.40 mg/dL, P = 0.0003) and VLDL (300.40 mg/dL, P = 0.0252) contents. A decreased content of thiobarbituric acid reactive substances (TBARS) and lower catalase activity was observed in the liver of quails from the CPS diet (0.086 nmoles/mg PTN, and 2.304 H₂O₂/min/mg PTN, respectively). Quails from the CPS group presented significantly greater expression of FAS (fatty acid synthase, 36,03 AU), ACC (Acetyl-CoA Carboxylase, 31.33 AU), APOAI (apolipoprotein A-I, 803,9 AU), ESR2 (estrogen receptor 2, 0.73 AU) SOD (superoxide dismutase, 4,933.9 AU) and GPx7 (glutathione peroxidase 7, 9.756 AU) than quails from the control group. These results allow us to suggest that cinnamon powder supplementation in the diet of laying quails can promote balance in the metabolism and better performance through the modulation of antioxidant activity and the expression of genes related to lipid metabolism.

Invited review: nutrient-sensing receptors for free fatty acids and hydroxycarboxylic acids in farm animals

Data on nutrient sensing by free fatty acid receptors (FFAR1, FFAR2, FFAR3, FFAR4) and hydroxycarboxylic acid receptors (HCAR1, HCAR2) are increasing for human or rodent models. Both receptor families link intestinal fermentation by the microbiota and energy metabolism with cellular responses. Therefore, this finding provides a link that is independent of the only function of the fermentation products as energy substrates. For example, these reactions are associated with insulin secretion, regulation of lipolysis, adipose tissue differentiation and innate immune responses. In farm animals, the available data on both receptor families from the intestine and other tissues increase. However, currently, the data are primarily linked with the distribution of receptor messenger RNAs (mRNAs) and more rarely with proteins. Functional data on the importance of these receptors in farm animal species is not abundant and is often associated with the immune system. In certain farm animal species, the receptors were cloned and ligand binding was characterised. In chicken, only one FFAR2 was recently identified using genome analysis, which is contradictory to a study using an FFAR1 small interfering RNA. The chicken FFAR2 is composed of more than 20 paralogs. No data on HCAR1 or HCAR2 exist in this species. Currently, in pigs, most available data are on the mRNA distribution within intestine. However, no FFAR1 expression has been shown in this organ to date. In addition to FFAR2, an orthologue (FFAR2-like) with the highest abundance in intestine has been reported. The data on HCAR1 and HCAR2 in pigs is scarce. In ruminants, most of the currently available information on receptor distribution is linked to mRNA data and shows the expression, for example, in mammary gland and adipose tissue. However, some protein data on FFAR2 and FFAR1 protein has been reported and functional data availability is slowly increasing. The receptor mRNAs of HCAR1 and HCAR2 are expressed in bovine. The HCAR2 protein has been demonstrated in certain tissues, such as liver and fat. Because of the physiological importance of both receptor families in human life science, more studies that analyse the physiological significance of both receptor families in animal science may be performed within the next several years.