The effects of the Saccharomyces cerevisiae extract on some organ, liver, and pancreatic digestive enzymes in breeder hens fed on aflatoxin (AF)-contaminated feed were investigated. Forty-eight 58-wk-old Ross 308 breeder hens were used. The hens were fed diets containing 0 or 100 µg of AF/kg and 0 or 1 g of S. cerevisiae/kg in a 2×2 factorial arrangement of treatments. Although serum alkaline phosphatase levels were significantly higher, serum alkaline aminotransferase (P=0.068) and gamma-glutamyltransferase (P=0.067) levels tended to increase (P<0.05) in hens fed the AF-contaminated diet than those of hens fed the uncontaminated diet. Both AF and S. cerevisiae extract increased (P<0.001) pancreatic amylase activity, but the effect was not additive, resulting in an AF×S. cerevisiae extract interaction (P<0.001). α-Amylase activity in duodenum was lower (P<0.001) in hens fed the AF-contaminated diet. Duodenum α-amylase activity was higher (P=0.024), but jejunum α-amylase activity was lower in S. cerevisiae extract-supplemented hens than that of nonsupplemented hens. There was a significant interaction between AF and S. cerevisiae extract on pancreatic and duodenal lipase activity. Pancreatic lipase activity decreased in hens fed the AF-contaminated diet. However, S. cerevisiae supplementation extract minimized this effect of AF on pancreatic lipase activity. Duodenal lipase activity was decreased in hens fed the AF-contaminated diet without S. cerevisiae extract supplementation. However, there were not any significant differences between hens fed the AF-contaminated diet and hens fed the uncontaminated diet after S. cerevisiae extract supplementation. Pancreatic trypsin activity was higher (P=0.044) in hens fed the AF-contaminated diet than that of hens fed the uncontaminated diet. There was a significant interaction between AF and S. cerevisiae extract on pancreatic chymotrypsin activity. It was increased in hens fed the AF-contaminated diet without S. cerevisiae extract supplementation. However, S. cerevisiae extract supplementation counteracted this negative effect of AF on pancreatic chymotrypsin activity. The treatments did not result in any change in duodenal chymotrypsin activity, but S. cerevisiae supplementation decreased (P<0.05) jejunal chymotrypsin activity. In conclusion, our results showed that addition of 1 g/kg of S. cerevisiae extract reduces the toxic effects of AF on pancreatic lipase and chymotrypsin activity. Therefore, it may be useful to supplement feedstuff with S. cerevisiae extract to reduce the effects of AF in laying breeder hens.

No abstract

The aim of the study was to examine the effects of cage furnishing and social stress on some lymphoid organ weight and innate, cell-mediated, and humoral immune responses in laying hens. Sixty-four chickens were used. The chickens were divided into 2 groups; one of the groups was reared in furnished cages (RFC) and the other was reared in conventional cages (RCC). In wk 17, social stress was applied. Heterophil and lymphocyte percentages; liver, spleen, thymus, and bursa of Fabricius weights; phagocytic activity; oxidative burst and chemotaxic activity of heterophil; CD4+ and CD8+ cell proportions; and antibody production were measured. The effect of rearing methods was significant on heterophil, lymphocyte percentage, heterophil/lymphocyte (H/L) ratio, and antibody production. Heterophil percentage and H/L ratio were lower (P=0.001, P=0.001, respectively), and antibody production was higher (P=0.003) in RFC hens compared to RCC hens. The main effect of social stress was also significant on heterophil, lymphocyte percentages, and H/L ratio. Heterophil percentage was higher (P=0.049); H/L ratio tended to be higher (P=0.068); and lymphocyte percentage tended to be lower (P=0.072) due to stress. In addition, thymus and bursa of Fabricius weights tended to be lower (P=0.073 and P=0.074, respectively) in stressed hens. There were significant interactions between rearing methods and social stress on oxidative burst, chemotaxic activity, and CD4+ and CD8+ proportion (P=0.001, P=0.004, P=0.054, and P=0.001, respectively). These parameters were significantly higher in RFC hens, when they were exposed to stress. On the other hand, they did not differ in RCC or unstressed RFC hens. These results indicated that cage furnishing positively affected heterophil functions, CD4+ and CD8+ cell proportions, and antibody production. Therefore, we suggest that cage furnishing, which is recommended for improving the welfare of animals, is also beneficial for improving the immune response of hens under the stress condition.

Long term ASA pretreatment could prevent and/or ameliorate certain hematological, serological and histological alterations caused by cerulein-induced AP.

No abstract

The effects of environmental enrichment and transport stress on the immune system were investigated in laying hens. A total of 48 1-day-old chickens were used, half of the chickens were reared in conventional cages (RCC) and the rest in enriched cages (REC). Transport stress was applied in the 17th week. Liver weight decreased, spleen and bursa of Fabricius weights, white blood cell count, CD4+ and CD8+ cell proportions increased due to the transport. Environmental enrichment significantly increased antibody production and tended to increase monocyte percentage and CD8+ cell proportion. The effect of transport on, heterophil (H) and lymphocyte (L) percentages was not significant in RCC chickens. While heterophil percentage and H:L ratio increased, lymphocyte percentage decreased in REC chickens subjected to transport. Transport stress increased heterophil functions both in REC and RCC chickens, but the increase was higher in REC hens than in RCC hens. In conclusion, although environmental enrichment did not neutralize the effect of transport on lymphoid organs, it activated the non-specific immune system, cellular and the humoral branches of the specific immune system by increasing heterophil functions, CD8+ cells and antibody production, respectively. Therefore, environmental enrichment suggested for improving animal welfare may also be beneficial to improve the immune system of birds exposed to stress.

The study was conducted to investigate the efficacy of Saccharomyces cerevisiae extract (SC) on haematological parameters, immune function, and the antioxidant defence system in breeder hens fed a diet contaminated with low level aflatoxin (AF). Forty-eight Ross 308 breeder hens were fed on diets containing AF (0 or 100 µg/kg) and SC (0 or 1 g/kg) in a 2 × 2 factorial arrangement. Red blood cell (RBC), white blood cell (WBC), and platelet counts, differential leucocyte counts, blood CD3+, CD4+, CD8+ and CD5+ T cell ratios, phagocytic activity and oxidative burst of heterophils, plasma and liver catalase activity, and malondialdehyde (MDA) and ascorbic acid concentrations were measured. 3. Plasma and liver MDA concentrations increased (P < 0·05), liver catalase activity decreased (P < 0·05) and total WBC count tended to decrease (P = 0·082) in hens fed the contaminated diet. WBC count, monocyte percentage, phagocytic activity and oxidative burst of heterophils increased (P < 0·05), and plasma MDA concentration tended to decrease (P = 0.088) in SC extract supplemented hens. There was a significant interaction between AF and SC on heterophil, lymphocyte, CD5+ cell percentages, and plasma catalase activity. Blood heterophil percentage decreased but lymphocyte percentage increased in hens fed on the AF contaminated diet without SC supplementation. SC supplementation counteracted the negative effect of AF on heterophils and lymphocytes. The CD5+ cell percentage decreased in unsupplemented hens fed the AF contaminated diet and this negative effect was minimised in SC supplemented hens. Plasma catalase activity increased in SC supplemented hens fed the uncontaminated diet whereas the effect of SC decreased in hens fed the AF contaminated diet. 4. The SC reduced some of the some adverse effects of AF, and improved functions of the non-specific immune system. Therefore, the SC extract which has been used for improving productive performance in birds and mammals may also be useful for modulating some of the effects of a low level, chronic dosage of AF.

Procalcitonin is the precursor of calcitonin hormone, produced by C cells of thyroid gland in physiological conditions. It is also produced in parenchymal cells of many tissues and leukocytes in pathological situations. In the normal condition, procalcitonin is converted by specific enzymes to the calcitonin. Therefore, it is amount in circulation is very low. On the contrary, it increases in the blood and tissue during diseases, because the procalcitonin produced in parenchymal cells cannot be converted to calcitonin. A great number of data has been documented about procalcitonin in human at the physiological and pathological conditions. Furthermore, productions, genetic regulation, kinetics, analysis methods, it is relation with cytokines and diseases have been studied extensively. Consequently, it is used as a reliable biomarker in human medicine, particularly for widespread bacterial infections. However, little is known about the implications in veterinary medicine. In terms of lightening the veterinary field, basic information and new findings on procalcitonin has been reviewed once more, although, quite a few studies have been conducted on procalcitonin in domestic or farm animals. The findings show that production and kinetics of procalcitonin in animals may be quite different, in both of the normal or pathologic conditions. It is not yet used as a biomarker in veterinary medicine. In addition, it has not yet been investigated whether it has an effect on reducing the antibiotics usage in animals.