The experiment was conducted to study the effects of different selenium source on selenium distribution, loin quality and antioxidant status in finishing pigs. A total of 108 castrates (Duroc×Landrace×Yorkshire) at average body weight (BW) of 60 kg were allotted to three treatments, each of which was replicated three times with 12 pigs per replicate (four per pen). The control groups received the basal diet containing 0.045 mg Se/kg. A 0.3 mg Se/kg in forms of sodium selenite or selenomethionine was added to the basal diet for the experimental groups. The total test period was 40 d. Results showed that selenomethionine-treatment increased the Hunter a (redness) value of meat color during 45 min, 8 and 16 h measurement period (P<0.05) and decreased the drip loss of loin muscle during 8 and 16 h measurement period (P<0.05), while sodium selenite-treatment only elevated the Hunter a value of meat color during 0.75 h measurement period (P<0.05) and had no significant effects on drip loss of loin muscle tissues. Both selenomethionine and sodium selenite-treatment increased the Se content in serum, muscle, liver, pancreas and kidney tissue (P<0.05), the level was substantially higher in muscle, liver and pancreas (P<0.05) in the selenomethionine treated group. In addition, both selenomethionine and sodium selenite-treatment increased glutathione peroxidase (GSH-Px) activity (P<0.05) and decreased the malondialdehyde (MDA) content in the liver and muscle (P<0.05) when compared with control group, but the level of magnitude was higher when selenomethionine was fed. The present study suggests that compared with sodium selenite, selenomethionine is more effective in depositing Se in tissues, enhances the antioxidant status, thus decreasing the volume of drip loss and stabilizing the meat color.

The effects of chronic fluoride exposure on kidney integrity and histological structure, along with effects on associated enzymes and metabolite changes, were investigated in young pigs. Twenty-four crossbred barrows (Duroc×Landrace×Yorkshire) about 50 days old were randomly divided into three groups of eight pigs each. Groups I, II, and III received the same basal diet additionally supplemented, respectively, with 0, 100, and 250 mg F–/kg (from NaF). Results obtained after 50 days indicated that supplemental fluoride-treatment caused severe renal histological changes as well as increased renal cell apoptosis. In kidney tissue, lactate dehydrogenenase (LDH) activity was significantly increased in group III, whereas alkaline phosphatase (AKP) activity was significantly decreased in group II as well as in group III. In the serum, significantly increased urea nitrogen (UN) was present in groups II and III, and the serum of group III had elevated creatinine (Cre) and decreased Na+. These findings show that chronic excessive fluoride exposure is deleterious to kidney structure and function of pigs.

This study was undertaken to investigate the effects of fluoride on growth and thyroid function in young pigs. Three groups of eight crossbred barrows were exposed to 100, 250, and 400 mg F-/kg (from NaF) in their diets for 50 days. Compared to a control group of eight pigs, the average daily gain in weight was significantly reduced, and serum thyroxine (T4) and free thyroxine (FT4) levels also decreased significantly. On the other hand, the level of serum thyroid-stimulating hormone (TSH) was significantly increased, but no significant differences were observed in serum triiodothyronine (T3) and free triiodothyronine (FT3). The activity of Na/K-ATPase in the thyroid was significantly inhibited as well as thyroid peroxidase (TPO). The results suggest that excessive fluoride in the diet can cause growth depression and hypothyroxinemia in pigs. Accompanying thyroid lesions were attributed to fluoride acting as a TSH analogue in concert with elevated TSH levels.

This study was conducted to investigate effects of fluoride on lipid peroxidation and antioxidant systems in young pigs. Three groups of crossbred barrows about 50 days old were exposed to 100, 250, and 400 mg F–/kg (from NaF) in their diets for 50 days. Serum malondialdehyde (MDA) and nitric oxide (NO) levels were significantly increased, and the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) were significantly decreased. In thyroid, liver, and kidney tissues, the MDA level was significantly increased, and SOD and GSH-Px activities were significantly decreased. These results suggest that fluoride induces excessive production of NO and reactive oxygen species (ROS), enhances lipid peroxidation, and disturbs the antioxidant system of pigs. Oxidative damage from oxidative stress could therefore be an important pathway for fluoride toxicity in soft tissues.

This study was conducted to investigate the effects of fluoride on pancreatic digestive enzyme activities and ultrastructure in young pigs. Three groups of crossbred barrows were exposed to 100, 250, and 400 mg F-/kg (from NaF) in their diets for 50 days. Compared to a control group, the activities of pancreatic lipase and protease (but not amylase) were significantly decreased. Pancreatic acinar cells showed markedly swollen mitochondria and loss of mitochondrial cristae. Endoplasmic reticulum (ER) was markedly dilated and its folds were irregular. These results indicate that excessive fluoride in the diet can inhibit pancreatic digestive enzyme activities and cause ultrastructural changes, which may lead to a series of biochemical and pathological abnormalities.