Expression patterns of natriuretic peptides in pre-hibernating and hibernating Anatolian ground squirrel (Spermophilus xanthoprymnus) kidney.

Hibernation is characterized by marked suppression of renal function. Natriuretic peptides (NPs) are involved in the regulation of renal function. However, the role of NPs in the renal function during hibernation remains unclear. We aimed to investigate the distribution patterns of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP) in Anatolian ground squirrel (Spermophilus xanthoprymnus) kidneys during pre-hibernation and hibernation periods. Cortical proximal tubules showed weak ANP immunoreactivity, with moderate staining on the brush border during the pre-hibernation period. In the hibernation period, moderate ANP immunoreactivity was seen in cortical proximal tubules, with very weak reaction in hibernating cortical distal tubules, medullary proximal and collecting tubules. Cortical proximal and distal tubules of both periods had strong and weak BNP immunoreactivity, respectively. Medullary proximal, distal and Henle's loop segments showed very weak BNP immunoreactivity during pre-hibernation. Medullary distal, proximal and collecting tubules and Henle's loop segments had moderate staining during hibernation. In both periods, cortical proximal tubules displayed strong immunoreactivity to CNP. Distal tubules had moderate CNP staining during pre-hibernation, albeit weak staining during hibernation. Medullary proximal tubules exhibited moderate to strong immunoreactivity during pre-hibernation. Medullary distal and proximal tubules had weak and moderate CNP staining, respectively, during pre-hibernation. In both periods, Henle's loop segments displayed moderate CNP immunoreactivity. Glomeruli had similar weak ANP, BNP and CNP staining in both periods. These results suggest that heterothermic conditions differently affected the expression of NPs in the squirrel kidney. This different expression of NPs may contribute to the renal adaptation during hibernation.

Effects of vitamin and mineral premix withdrawal from diets on carcass and meat quality of feedlot steers.

The primary objective of the present study was to assess the effects of vitamin and mineral premix (VMP) withdrawal from the diets 30 and 60 days ahead of slaughter on carcass and meat quality of Holstein Friesian steers. A total of 45 animals at 16 to 17 months of age were used and the selected animals were divided into three experimental groups: control group (fed with a diet with VMP), VMP withdrawal 30 days ahead of slaughter (VMP30 group), and VMP withdrawal 60 days ahead of slaughter (VMP60 group). Meat samples were taken at 24 h postmortem from the 13th rib section and meat quality was evaluated on the Longissimus dorsi thoracis (LT) muscle. After slaughter, carcass yield and meat drip loss, cooking loss, thawing loss, and shear force traits were determined. Meat pH and color parameters were measured at 24, 48, 72, 96, 120, and 144 h of postmortem. The fatty acid composition in 13th rib section' adipose tissue was determined. The hot and cold carcass weights, carcass yield and chilling loss were not affected by the withdrawal of VMP from the diet. Withdrawal of VMP from the diets 30 and 60 days ahead of slaughter did not have any significant effects on ultimate pH, drip loss, cooking loss, thawing loss, shear force, and meat color. Additionally, dry matter, crude protein, ash, fat contents, moisture-protein ratio of the meat samples, and fatty acid profiles were not affected by VMP30 and VMP60 treatments. It was concluded based on present finding VMP could be withdrawn safely from the diets 30 and 60 days ahead of slaughter without any negative effects on carcass and meat quality traits of feedlot steers. Withdrawal of VMP may reduce feeding costs and environmental damages generated by animal breeding systems.