The meat quality of chicken is an important factor affecting the consumer’s health. It was hypothesized that n-3 polyunsaturated fatty acid (n-3 PUFA) could be effectively deposited in chicken, by incorporating antioxidation of soybean isoflavone (SI), which led to improved quality of chicken meat for good health of human beings. Effects of partial or complete dietary substitution of lard (LA) with linseed oil (LO), with or without SI on growth performance, biochemical indicators, meat quality, fatty acid profiles, lipid-related health indicators and gene expression of breast muscle were examined in chickens. A total of 900 males were fed a corn–soybean meal diet supplemented with 4% LA, 2% LA + 2% LO and 4% LO and the latter two including 30 mg SI/kg (2% LA + 2% LO + SI and 4% LO + SI) from 29 to 66 days of age; each of the five dietary treatments included six replicates of 30 birds. Compared with the 4% LA diet, dietary 4% LO significantly increased the feed efficiency and had no negative effect on objective indices related to meat quality; LO significantly decreased plasma triglycerides and total cholesterol (TCH); abdominal fat percentage was significantly decreased in birds fed the 4% LO and 4% LO + SI diets. Chickens with LO diets resulted in higher contents of α-linolenic acid (C18:3n-3), EPA (C20:5n-3) and total n-3 PUFA, together with a lower content of palmitic acid (C16:0), lignoceric acid (C24:0), saturated fatty acids and n-6:n-3 ratio in breast muscle compared to 4% LA diet (P < 0.05); they also significantly decreased atherogenic index, thrombogenic index and increased the hypocholesterolemic to hypercholesterolemic ratio. Adding SI to the LO diets enhanced the contents of EPA and DHA (C22:6n-3), plasma total superoxide dismutase, reduced glutathione (GSH)/oxidized glutathione and muscle GSH content, while decreased plasma total triglyceride and TCH and malondialdehyde content in plasma and breast muscle compared to its absence (P < 0.05). Expression in breast muscle of fatty acid desaturase 1 (FADS1), FADS2, elongase 2 (ELOVL2) and ELOVL5 genes were significantly higher with the LO diets including SI than with the 4% LA diet. Significant interactions existed between LO level and inclusion of SI on EPA and TCH contents. These findings indicate that diet supplemented with LO combined with SI is an effective alternative when optimizing the nutritional value of chicken meat for human consumers.

In the present study, the mRNA levels of hepatic proteins involved in the drug metabolism of rats fed α-lipoic acid were evaluated by DNA microarray and real-time PCR analyses. Experimental diets containing 0, 0·1, 0·25 and 0·5 % (w/w) α-lipoic acid were fed to four groups of rats consisting of seven animals each for 21 d. DNA microarray analysis revealed that the diet containing 0·5 % α-lipoic acid significantly (P< 0·05) increased the mRNA levels of various phase I drug-metabolising enzymes up to 15-fold and phase II enzymes up to 52-fold in an isoenzyme-specific manner. α-Lipoic acid also up-regulated the mRNA levels of some members of the ATP-binding cassette transporter superfamily, presumed to be involved in the exportation of xenobiotics, up to 6·6-fold. In addition, we observed that α-lipoic acid increased the mRNA levels of many proteins involved in antioxidation, such as members of the thiol redox system (up to 5·5-fold), metallothioneins (up to 12-fold) and haeme oxygenase 1 (1·5-fold). These results were confirmed using real-time PCR analysis, and α-lipoic acid dose dependently increased the mRNA levels of various proteins involved in drug metabolism and antioxidation. Consistent with these observations, α-lipoic acid dose dependently increased the hepatic concentration of glutathione and the activities of glutathione reductase and glutathione transferase measured using 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene as substrates, but decreased the hepatic and serum concentrations of malondialdehyde. In conclusion, the present study unequivocally demonstrated that α-lipoic acid increases the mRNA expression of proteins involved in drug metabolism and antioxidation in the liver.

The present study was conducted to evaluate the immune-enhancing effects of dietary l-glutamine supplementation in porcine circovirus type 2 (PCV2)-infected mice, and to examine the clearance effects of glutamine against PCV2 in experimentally infected mice. A total of sixty Kunming female mice were infected with PCV2 at a dose of 100 TCID50 (50 % tissue culture infection dose) by intraperitoneal injection after 2 weeks of dietary l-glutamine supplementation or l-alanine supplementation (as the control (isonitrogenous) group). The measured variables on 3rd, 5th, 7th, 9th and 11th d post-infection (dpi) included: (1) PCV2 virus loaded in the liver, spleen, heart, lung, kidney, ovary and serum was determined by real-time PCR; (2) IL-2, IL-6, IL-10, interferon (IFN)-α, IFN-γ and C-reactive protein levels in serum were measured by ELISA; (3) serum total superoxide dismutase activity was measured spectrophotometrically at 550 nm absorbance. Dietary l-glutamine supplementation significantly increased serum IL-2 levels on the 3rd (P< 0·01), 5th (P< 0·01), 7th (P< 0·05) and 9th dpi, significantly (P< 0·05) increased serum IL-6 levels on 3rd dpi, significantly (P< 0·05) increased serum IFN-γ levels on the 9th and 11th dpi and significantly decreased (P< 0·01) serum IL-10 levels on the 9th and 11th dpi, compared with those in the control group. Meanwhile, the PCV2 virus genome was detected sporadically throughout the experimental period in both groups. Taken together, the present results suggest that dietary l-glutamine supplementation enhances immune function in PCV2-infected mice.

L-carnitine has indispensable functions in intermediary metabolism and is received by endogenous synthesis and from exogenous sources. It plays an obligate role in fatty acid metabolism by directing fatty acids into the mitochondrial oxidative pathway through the action of specialised acyltransferases. In poultry production, L-carnitine has a multi functional purpose, which includes: growth promotion, strengthening the immune system, antioxidant effects and improving semen quality. The concentration of L-carnitine in animals varies widely across species, tissue type, and nutritional status of the animal. It has been suggested that the L-carnitine requirement may be increased under certain circumstances such as via higher performance, various stress conditions and where the diet is deficient in animal protein sources. The review of L-carnitine functions uniquely includes the main aspects of this consequential feed supplementary inclusion in poultry nutrition.

In order to investigate the long-term effects of equol (Eq) on growth and meat quality in broilers, 0 μg (control, Con), 20 μg (low dose, L) and 100 μg (high dose, H) Eq, respectively, were injected into fertile eggs (146 eggs per group) on 7 days of embryos. After hatch, chickens were fed under the same conditions and slaughtered at 49 days of age for sample collection and analysis. The results showed that body weight and composition were marginally affected by Eq administration (P > 0.05). Compared with their male counterparts, the meat quality of female broilers was affected greatly after Eq administration. The redness (a*) of meat color in the L and H groups of female broilers was significantly decreased by 24.10% and 21.50% (P < 0.01), respectively; cooking loss decreased by 12.11% and 16.82%, respectively, in the L and H groups (P < 0.01); 24 h and 48 h drip loss was significantly decreased by 60.27% and 45.72% (P < 0.05), respectively, in the H group. However, for male broilers, only cooking loss was significantly decreased by high dosage of Eq treatment (P < 0.05). The antioxidative status was analyzed for discovering further the mechanism behind the improvement of the water-holding capacity caused by Eq in female broilers. The activity of glutathione peroxidase (GSHPx) in plasma was greatly increased by 15.94% in the L group (P < 0.01), whereas the total superoxide dismutase activity (T-SOD) and the content of malondialdehyde in plasma were not changed (P > 0.05). The T-SOD activity in the breast muscle of the L and H groups were significantly improved by 23.14% and 18.82% (P < 0.05), respectively. GSHPx in the breast muscle of the H group showed a tendency to increase (P = 0.06 < 0.1). These results indicate that Eq injection in ovo does not affect the growth of broilers, but significantly improves the water-holding capacity of the muscle, especially in female broilers, which is related to the improvement of antioxidative status.

It has been observed that the levels of brain monoamine oxidase B (MAO-B) increase during ageing. MAO catalyses the oxidative deamination of neurotransmitters, in which the by-product H2O2 is subsequently generated. Se exists naturally in inorganic and organic forms and is considered to play a key role in antioxidation functioning. The objective of the present study was to investigate two chemical forms of Se compounds for their inhibition effect on rat brain MAO-B. The total antioxidant capacity and lipid peroxidation of rats were also examined. The rats (age 7 weeks) were divided into four groups: the control group, tocopherol group (T group, positive control), selenite group (SE group, representing the inorganic Se group) and seleno-yeast group (SY group, representing the organic Se group). The rats were fed for 11 weeks with normal diets and 12 weeks with test diets. The serum total antioxidant capacity of the SE and SY groups was significantly higher than that in the control and T groups. In rat brains and livers, the lipid peroxidation levels were significantly decreased in the T, SE and SY groups. MAO-B activity showed a significant decrease in the T, SE and SY groups in rat brains but no significant change could be noted in the rat livers. In conclusion, the present study indicates that inorganic or organic Se supplementation can decrease the brain MAO-B enzyme activity in adult rats and can be accomplished by the effect of the Se antioxidation capability.

This study investigated the effects of β-carotene and canthaxanthin on lipid peroxidation and antioxidative enzyme activities in rats fed a high-cholesterol, high-fat diet. Wistar rats were divided into six groups. Negative control group (group NC) received a high-fat (150 g/kg) diet; cholesterol control group (group CC) received a high-cholesterol (10 g/kg), high-fat diet. The other four groups were fed a high-cholesterol, high-fat diet supplemented with crystal β-carotene (group BC), β-carotene beadlet (group BB), canthaxanthin beadlet (group CX) or α-tocopherol (group AT). Blood and livers were collected for analysis after 6 weeks of feeding. Group BB had significantly lower hepatic thiobarbituric acid reactive substance (TBARS) and conjugated diene concentrations, whereas group CX had a significantly lower plasma TBARS concentration than did group CC. In erythrocytes, glutathione peroxidase activities were significantly greater in groups BC, BB and CX than in group CC. Moreover, compared with group CC, catalase activities were significantly greater in groups BB and CX, and superoxide dismutase (SOD) activity was significantly greater in group BB. In livers, SOD activities were significantly greater in groups BC, BB and CX, and glutathione reductase activities were significantly greater in groups BB and CX than in group CC. Compared with group CC, hepatic retinol and α-tocopherol concentrations were significantly greater in groups BC, BB and CX, whereas plasma and hepatic cholesterol concentrations were significantly lower in group BC. These findings suggest that β-carotene and canthaxanthin altered the pro-oxidation and antioxidation balance and suppressed cholesterol-induced oxidative stress via modulation of antioxidant system and cholesterol metabolism.