Effects of Zinc Oxide Nanoparticles on Growth, Intestinal Barrier, Oxidative Status and Mineral Deposition in 21-Day-Old Broiler Chicks

This experiment was to study the effects of zinc oxide nanoparticles (ZnO-NPs) on growth, intestinal barrier, oxidative status, and mineral deposition. In total, 256 one-day-old chicks were randomly allotted to 4 dietary groups and fed with basal diet plus 80 mg/kg ZnSO₄ (ZnSO₄ group) or plus 40, 80, and 160 mg/kg ZnO-NPs, respectively, for 21 days. Compared with the ZnSO₄ group, dietary 40, 80, and 160 mg/kg ZnO-NPs did not alter growth (average daily gain, body weight, and gain to feed ratio), and serum activities of glutamic-pyruvic transaminase, alkaline phosphatase and glutamic oxalacetic transaminase (P > 0.05). However, dietary 80 and 160 mg/kg ZnO-NPs linearly decreased serum D-lactate content and diamine oxidase activity (P < 0.01). Moreover, 80 mg/kg ZnO-NPs enhanced zonula occludens-1 (ZO-1) mRNA expression in jejunal mucosa (P = 0.02). Dietary ZnO-NPs increased total antioxidant capacity activity (P = 0.01), and 80 mg/kg ZnO-NPs decreased malondialdehyde content in jejunal mucosa as compared to the ZnSO₄ group (P = 0.02). In contrast, dietary ZnO-NPs did not alter mRNA expressions of superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, heme oxygennase-1 (HO-1) and NAD (P)H: quinone oxidoreductase 1 (NQO1) (P > 0.05). No significant difference was found in selected mineral concentrations (Mn, Cu, Fe and Zn) in the liver among ZnSO₄ and 3 ZnO-NP groups (P > 0.05). However, 160 mg/kg ZnO-NPs increased fecal contents of Zn, Fe and Cu (P < 0.01), but did not affect fecal Mn level (P > 0.05). Therefore, results suggested that ZnO-NPs could be an additive to enhance the intestinal barrier and antioxidant capacity of broiler chicks, whereas the inclusion of 80 mg/kg would be more efficient.

Ferulic acid, a phytochemical with transient anorexigenic effects in birds

Ferulic acid (FA) is a phenolic acid found within the plant cell wall that has physiological benefits as an antioxidant. Although metabolic benefits of FA supplementation are described, lacking are reports of effects on appetite regulation. Thus, our objective was to determine if FA affects food or water intake, using chicks as a model. At 4 days post-hatch, broiler chicks were intraperitoneally injected with 0 (vehicle), 12.5, 25, or 50 mg/kg of FA. Chicks treated with 50 mg/kg of FA consumed 70% less food than controls at 30 min post-injection, and the effect dissipated thereafter. Water intake was not affected at any time. In a behavior analysis, FA-treated chicks defecated fewer times than vehicle-injected chicks, while other behaviors were not affected. There was an increase in c-Fos immunoreactivity within the hypothalamic arcuate nucleus (ARC) of FA-treated chicks, and no differences were detected in other nuclei. mRNA abundance was measured in the whole hypothalamus and the ARC. There was decreased hypothalamic galanin, ghrelin, melanocortin receptor 3, and pro-opiomelanocortin (POMC) mRNA in FA-treated chicks. Within the ARC, there was an increase in c-Fos mRNA and a decrease in POMC mRNA in response to FA. It is likely that the mechanism responsible for mediating FA's transient effects on food intake originates within the ARC, possibly involving POMC. A greater understanding of the short-term, mild appetite-suppressive effects of FA may have applications to treating eating disorders and modulating food intake in animal models of obesity.

Central administration of insulin and refeeding lead to the phosphorylation of AKT, but not FOXO1, in the hypothalamus of broiler chicks

Several studies in rodents and layer chickens have demonstrated that insulin upregulates hypothalamic AKT-mediated signaling and expression of proopiomelanocortin (POMC, the precursor of alpha-melanocyte stimulating hormone, an anorexigenic peptide) and suppresses appetite in these animals. However, a previous study has also reported that insulin fails to suppress food intake in broiler chicks. In the present study, no significant differences were observed in hypothalamic AKT and forkhead box O1 (FOXO1) phosphorylation levels between broiler and layer chicks. The phosphorylation rate of AKT, but not that of FOXO1, increased in the hypothalami of broilers refed for 1 h after a 24-h fast, with a corresponding increase in plasma insulin concentration. Intracerebroventricular (ICV) administration of 50 pmol insulin, which could decrease food intake in broiler chicks, significantly increased the AKT phosphorylation rate, whereas no significant change was observed in FOXO1 phosphorylation or POMC expression after ICV insulin administration. These findings suggest that hypothalamic AKT responds to insulin in broiler chicks, but FOXO1-mediated regulation of POMC expression is not induced by insulin, which may be one of the causes of excessive food intake in broiler chickens.

Distribution of TLR4 and MHC class II molecules of the spleen in broiler chicks treated with and without LPS in the first 2 weeks of the post-hatch period

1. The purpose of this study was to investigate the distribution of Toll-like receptor-4 (TLR4) and major histocompatibility complex (MHC) class II molecules of the spleen in chicks treated with lipopolysaccharide (LPS) during the first 2 weeks of their life. 2. A total of 225 Ross-308 commercial broiler chicks were used. Within the 2-week experimental period, chicks were divided into 5 main groups according to the days of decapitation which were 1, 4, 7, 10 and 14 d after hatch. Each main group had 45 chicks. The main groups were further divided into three subgroups (15 chicks each), which included control chicks (no injection), and phosphate-buffered saline (PBS) and LPS-injected chicks. Spleen samples were collected 1-, 3-, 6-, 12- and 24-h after the PBS or LPS administrations. Tissue sections were stained using streptavidin-biotin-peroxidase complex staining method. 3. From 1 d of age, TLR4 positivity was found in the spleen in diffuse granular form. The cells showing intense TLR4 positivity were observed in periellipsoidal lymphoid tissue in 4-d-old chicks. The same cells were determined in the germinal centre of the spleen in 7-d-old chicks. LPS stimulation led to an increase in the intensity of TLR4 positivity in 14-d-old chicks. 4. From 1 d of age, MHC class II positivity was found in both white pulp and red pulp. This was higher in 14-d-old chicks injected with LPS than in the controls and the chicks injected with PBS. 5. The findings indicate that, from 1 d of age in chicks, the spleen has both non-specific defence elements and the molecules having the information to induce adaptive immunity. In addition, at the end of the 2-week experimental period, it was determined that the spleen had the capacity to recognise antigens.

Effect of amount and duration of waste green tea powder on the growth performance, carcass characteristics, blood parameters, and lipid metabolites of growing broilers

This study has evaluated the possible effect of waste powder of green tea (Camellia sinensis) in feed supplementation on the growth performance, carcass characteristics, blood parameters, and lipid metabolites of growing broilers (chicks) in both the amount and duration aspects of dietary additives during the finisher phases. In the experiment, growth performance, carcass characteristics, blood parameters, and lipid metabolites of broiler chicks have been fully recorded and explored. The diet of 271 day-old Ross 308 male broiler chicks has been supplemented with 0, 0.25, 0.50, 0.75, and 1.00% (w/w) green tea powder in addition to normal feeding additives. The experiment lasted for 21 and 42 days, respectively, for each value of the green tea supplement and for separate groups of animals. Broiler feed has been supplemented with different levels of green tea powder to assess the trial effect and potential beneficial dose on selected growth performance, carcass characteristics, and blood parameters of broiler chicks. Although there are almost no differences of broiler parameters and characteristics measured from one point of view of single treatment factor (amount or duration), against the control groups during the three trial periods, the overall effect of amount and duration of feeding green tea powder is positive on growth performance, carcass characteristics, blood parameters, and lipid metabolites of growing broilers, although there are nearly no differences in some broiler parameters and characteristics. However, there are a remarkable interactive effect of amount and duration of different feeding levels of green tea powder and obvious differences observed in all the parameters and characteristics of growing broilers. Especially, usage of feeding green tea powder largely decreased the abdominal fat content and some lipid metabolites, including VLDL cholesterol, LDL cholesterol, triglycerides, and AST of broiler chicks. While additional data are still needed to evaluate and analyze the optimum supplement feed doses, it can be concluded that dietary green tea is a positive feed supplementation to reduce abdominal fat and lipid metabolites and induce antioxidants.

Hypervitaminosis D3 in broiler chicks: histopathological, immunomodulatory and immunohistochemical approach

The present study was undertaken to investigate the toxic effects of higher doses (1,00,000 IU i.e. 2.5 mg/kg body weight (BW)) of vitamin D₃, concomitantly with bacterial endotoxins (lipopolysaccharides: LPS) to study the immunomodulatory potential of vitamin D₃ in IBL-80 broiler chicks. The chicks were divided into four groups [group I (NSS), group II (LPS), group III (Vit. D₃ + NSS), and group IV (Vit. D₃ + LPS)] containing eight chicks in each group, treated accordingly for 21 days. Birds were kept under close observation for apparent clinical signs and symptoms. Clinically, vitamin D₃ treated chicks were dull, off feed, showed polydipsia, polyuria, watery faeces, rigidity of limbs, severe dehydration, weakness and significant progressive emaciation. Grossly, the bones were soft whereas most organs revealed congestion and hemorrhages in visceral organs. Histopathologically, renal tubular epithelium showed coagulative necrosis and metastatic calcification. The lung parenchyma and bronchi showed hemorrhages, congestion with diffuse heterophilic cell infiltration in inter-alveolar septa and infiltration of heterophils in alveoli along with proteinacious fluid in LPS treated chicks of treatment group, suggesting immunomodulatory action of vitamin D₃. Vitamin D₃ treated chicks showed strong expression of Calbindin D28k in intestine and kidney but weak expression in lung, which can be linked to nephrocalcinosis seen in kidney and from its prospective role in cellular calcium homeostasis.

The Functions of Antioxidants and Heat Shock Proteins Are Altered in the Immune Organs of Selenium-Deficient Broiler Chickens

Despite increasing evidence indicating the essential involvement of selenium (Se) in the immune system, the effect of Se deficiency on the regulation of oxidative stress and heat shock proteins (Hsps) in broiler chickens is still unclear. In the present study, we established an exudative diathesis (ED) broiler chicken model caused by Se deficiency. We then analyzed histological observations and detected the expression levels of Hsps and antioxidant indexes in immune tissues. The antioxidant function declined remarkably, and most of the Hsp expression levels increased significantly in the spleen, thymus, and bursa of Fabricius of the broiler chicks with ED (except the messenger RNA (mRNA) levels of Hsp27, Hsp40, and Hsp70, which decreased in thymus tissues from the treatment groups); therefore, constitutive oxidation resistance and higher Hsps in broiler chicks with ED caused defects in immune organ morphology and function, as evidenced by abnormal histological structures: red pulp broadening and lymphocytes in the cortex and medulla of the thymic lobule decreased distinctly and distributed loosely. These results underscore the importance of Se in establishing an immune organ microenvironment conducive to normal function.