Effects of supplementing two levels of magnesium aspartate and transportation stress on pork quality and gene expression of 𝛍-calpain and calpastatin of finishing pigs

The objective of this study was to investigate the effects of supplementing swine finishing diets with two levels of magnesium aspartate (MgAsp) and short-term transportation stress on blood parameters, pork quality and the mRNA abundance of μ-calpain and calpastatin in muscles of finishing pigs. Thirty-six crossbred finishing pigs (mean BW 90 kg) were assigned randomly to 0, 1000, or 2000 mg supplemental Mg from MgAsp per kg of diet for five days before slaughter. Then six pigs from each dietary treatment were subjected either to no transportation stress (NTS) or 2 h of transportation stress (TS). Transportation stress resulted in higher concentrations (p < 0.01) of serum calcium, glucose and cortisol, lower pH (p < 0.01), higher Warner-Bratzler shear force (WBSF) (p < 0.05) and higher calpastatin mRNA abundance (p = 0.05) of longissimus muscle (LM) compared with NTS treatments. Supplementation of MgAsp in TS treatments increased serum Mg concentration (p < 0.05) at 2000 mg of Mg/kg, reduced drip loss (p < 0.05) and improved pork quality colour (p < 0.05) at 2000 mg of Mg/kg, and decreased 1-day and 3-day WBSF (p < 0.05) at 1000 mg of Mg/kg compared with TS treatments fed the control diet. It is concluded that supplementation of MgAsp improves water-holding capacity and pork colour, and alleviates the negative effects of transportation stress on meat tenderness.     

Effects of source and level of magnesium on catalase activity and its gene expression in livers of broiler chickens

The effects of dietary supplemental magnesium oxide (MgO), magnesium-L-aspartate (MgAsp) and monomagnesium-di-L-aspartate (MgdiAsp) on hepatic catalase (CAT) activity and its mRNA expression were investigated. A total of 360 one-day-old male Abor Acre broiler chickens were allocated to ten treatments, i.e. control plus 9 treatments from 3 x 3 factorial arrangement (Mg source, Mg level), each treatment with six replicates of 6 chickens. The birds were fed with the basal diet alone or supplemented with magnesium (Mg) at 0.9, 1.8, 2.7 g/kg of the diet from MgO, MgAsp or MgdiAsp. Results showed that hepatic Mg concentration increased quadratically as MgO or MgAsp supplementation increased (p < 0.01). Hepatic CAT activity increased linearly in birds fed with MgAsp or MgdiAsp (p < 0.01) and quadratically in birds fed with MgO (p < 0.05) as dietary Mg supplementation level increased. Hepatic CAT mRNA was linearly correlated with the dietary Mg supplementation level (p < 0.01). There were positive correlations among hepatic CAT activity, its mRNA expression level and hepatic Mg concentration (p < 0.01). No effect of Mg2+ on the purified CAT activity was detected in vitro enzymatic reaction system (p > 0.05). Supplemental MgAsp or MgdiAsp was more efficient to increase hepatic Mg concentrations, enhance hepatic CAT activity and its mRNA expression than MgO (p < 0.01). It can be concluded that dietary Mg supplementation could increase hepatic Mg concentration, enhance CAT mRNA expression and consequently enhance CAT activity, and the organic Mg (MgAsp or MgdiAsp) is much more efficient than the inorganic form (MgO).     

Effects of source and level of magnesium on catalase activity and its gene expression in livers of broiler chickens

Abstract

The effects of dietary supplemental magnesium oxide (MgO), magnesium-L-aspartate (MgAsp) and monomagnesium-di-L-aspartate (MgdiAsp) on hepatic catalase (CAT) activity and its mRNA expression were investigated. A total of 360 one-day-old male Abor Acre broiler chickens were allocated to ten treatments, i.e. control plus 9 treatments from 3×3 factorial arrangement (Mg source, Mg level), each treatment with six replicates of 6 chickens. The birds were fed with the basal diet alone or supplemented with magnesium (Mg) at 0.9, 1.8, 2.7 g/kg of the diet from MgO, MgAsp or MgdiAsp. Results showed that hepatic Mg concentration increased quadratically as MgO or MgAsp supplementation increased (p < 0.01). Hepatic CAT activity increased linearly in birds fed with MgAsp or MgdiAsp (p < 0.01) and quadratically in birds fed with MgO (p < 0.05) as dietary Mg supplementation level increased. Hepatic CAT mRNA was linearly correlated with the dietary Mg supplementation level (p < 0.01). There were positive correlations among hepatic CAT activity, its mRNA expression level and hepatic Mg concentration (p < 0.01). No effect of Mg²⁺ on the purified CAT activity was detected in vitro enzymatic reaction system (p > 0.05). Supplemental MgAsp or MgdiAsp was more efficient to increase hepatic Mg concentrations, enhance hepatic CAT activity and its mRNA expression than MgO (p < 0.01). It can be concluded that dietary Mg supplementation could increase hepatic Mg concentration, enhance CAT mRNA expression and consequently enhance CAT activity, and the organic Mg (MgAsp or MgdiAsp) is much more efficient than the inorganic form (MgO).     

Methionine, folic acid and vitamin B12 in growing-finishing pigs: impact on growth performance and meat quality

Growth performance, metabolic variables, and meat quality were measured in 78 growing-finishing pigs using supplements of 0 (C), or 0.2% of DL-methionine (M), and three combinations of folic acid [mg/kg] and cyanocobalamin [microg/kg], respectively 0 and 0 (V0), 10 and 25 (V1), and 10 and 150 (V2) in a 2 x 3 factorial arrangement. Feed conversion was lower (p = 0.05) in M than in C pigs during the growing period (0-4 weeks). Both V1 and V2 treatments increased plasma vitamin B12 (p < 0.01) and decreased plasma homocysteine (p < 0.01). Plasma 5-methyl-tetrahydrofolates were the lowest, highest and intermediate in V0, V1 and V2 pigs (p < 0.04), respectively. In V2 meat, folates were 32% higher, vitamin B12, 55% higher and homocysteine, 28% lower than in V0 (p < 0.01). Oxidative stability of the fresh meat was similar among treatments during a storage period of 42 days. Therefore, methionine supplements improved growth performance during the growing period. Vitamin supplements interacted with the methionine cycle pathway, increased vitamin content of pork meat but did not improve oxidative stability of the fresh meat during storage.     

Effects of deep-bedded finishing system on market pig performance, composition and pork quality

The purpose of this study was to compare effects of finishing environment on growth performance, pork quality and lipid composition of pork. Environments compared were standard confinement (CON) and deep-bedded semi-outdoor systems. The deep-bedded method employed in the current study was the use of hoop structures. Hoops are large, tent-like shelters with cornstalks or straw for bedding. Gilts ranging in weight from 59 to 71 kg were randomly assigned to treatments of Hoop (n = 50) and CON (n = 18) environments. Gilts were fed a two-phase dietary sequence, ad libitum for 45 days. Six gilts per treatment were selected for carcass composition and quality evaluation. The experiment was replicated a total of five times. Pigs raised in the Hoop environment gained significantly less and required significantly more feed for growth than pigs raised in the CON environment. Carcasses from CON-finished pigs were significantly fatter at the 10th rib, which lowered carcass percentage fat-free lean(FFL) and they also had greater loin marbling scores compared with carcasses from Hoop-finished pigs (P < 0.05). Significant replication effects were noted on beginning weight, live weight, carcass weight, percentage FFL, backfat, lipid content and adipose firmness. Carcasses from Hoop pigs had lower proportions of palmitic acid (P < 0.05), and higher proportions of oleic and linoleic acid (P < 0.05) in the inner layer of adipose tissue. The proportion of saturated fatty acid was lower, and that of mono- and poly-unsaturated fatty acid was higher in the inner layer of the adipose tissue of Hoop pigs. Variations in fatty acid composition and lipid deposition may have been caused by environmental temperature, since decreases in environmental temperature accompanied compositional variation of the adipose, leading to higher proportions of monounsaturated fatty acid and lower proportions of saturated and polyunsaturated fatty acid in adipose tissue, regardless of treatment. Volatile profile analysis revealed that adipose tissue of Hoop pigs had significantly higher amounts of 3-butanal and heptanal compared with CON pigs, which may be related to the amount of oleic and linoleic acids composing the adipose tissue. These data indicate finishing pigs in hoop structures allows for exposure to fluctuating temperatures, which may influence the growth of pigs, as well as fatty acid composition and firmness of pork products.     

Dietary arginine supplementation enhances antioxidative capacity and improves meat quality of finishing pigs

The present study was conducted to test the hypothesis that dietary arginine supplementation may improve meat quality of finishing pigs. Beginning at ~60 kg body weight, pigs were fed a corn- and soybean meal-based diet supplemented with 0, 0.5 or 1% l-arginine until they reached a body weight of ~110 kg. On the last day of the experiment, pigs were food-deprived for 16 h before blood samples were obtained for analysis of amino acids, insulin, and other metabolites. Immediately thereafter, pigs were slaughtered for determination of carcass composition, muscle biochemical parameters, and meat quality. The result showed that arginine did not affect pig growth performance or carcass traits. However, 1% arginine decreased drip loss of pork muscle at 48 h postmortem, while increasing intramuscular fat content (P < 0.05). Supplementing 0.5 or 1% arginine to the diet increased arginine concentration and decreased cortisol level in serum, while enhancing antioxidative capacity and glutathione peroxidase activity in serum (P < 0.05). Additionally, 1% arginine increased antioxidative capacity in skeletal muscle (P < 0.05). Furthermore, 0.5 or 1% arginine decreased the cortisol receptor mRNA level in muscle (P < 0.05). Collectively, these results indicate that supplemental arginine improved meat quality and attenuated oxidative stress of finishing pigs.     

Effect of dietary crude protein levels in a commercial range, on the nitrogen balance, ammonia emission and pollutant characteristics of slurry in fattening pigs

An experiment was conducted to investigate the effect of dietary levels of crude protein (CP), close to the range used commercially and to the European Commission recommended values, on the nitrogen (N) balance, ammonia (NH(3)) emission and pollutant characteristics of the slurry from growing and finishing pigs. Three feeding programmes with different CP levels were compared during the growing and the finishing periods of fattening. Diets were formulated to be isoenergetic and for the digestible lysine : metabolisable energy ratio to be similar in all the diets for each phase, but differed in CP concentration (160, 150 and 140 g CP/kg for the growing phase and 155, 145 and 135 g CP/kg for the finishing phase). Faeces and urine from barrows (eight replicates per diet) allocated in metabolism cages were collected separately for 5 days to calculate the N balance and for 2 days to measure NH(3) emission in a laboratory system for 240 h. Excreta were analysed for pH, volatile fatty acids (VFA), total N, electrical conductivity (EC), total solids (TS), volatile solids (VS), biochemical oxygen demand (BOD(5)), chemical oxygen demand (COD) and NH(4)-N reduction of dietary CP content led to a linear decrease of urinary (P < 0.05) and total (P < 0.05) N excretion, and N excretion/feed intake (P < 0.001). The emission of NH3 was similar in all diets (P > 0.05) during the 240 h of study. However, in the growing phase, the NH(3)-N level in slurry was lower (P < 0.05) for the low-CP diet. In addition, the CP level had no significant effect (P > 0.05) on total VFA, EC, TS, VS, COD or BOD(5) contents of excreta. These parameters were higher (P < 0.05) in slurry from the finishing phase than from the growing phase. However, NH(4)-N in the slurry decreased (P < 0.05) by 20.3% and 28.4% when the CP level was decreased by 9.30 or 21.40 g/kg, respectively. It is concluded that lowering dietary CP levels even by small amounts and using CP levels close to these used in commercial diets and close to the European Commission recommended values will decrease urinary and total N excretion in the slurry of growing-finishing pigs. The slurry from finishing pigs is more concentrated than that from growing pigs.     

Effect of avilamycin and tylosin on the metabolizable energy in growing and finishing pigs

In two metabolism trials with growing and finishing pigs the influence of the antibiotic feed additives Avilamycin and Tylosin on the metabolizable energy was investigated at different levels of dietary protein content. In the first experiment (growing pigs) the antibiotics were supplied at levels of 0 mg/kg, 40 mg/kg Avilamycin and 40 mg/kg Tylosin to diets containing 18.5%, 17.5%, 16.5% and 14.0% of crude protein. In the second experiment (finishing pigs) 0 mg/kg antibiotics, 20 mg/kg Avilamycin and 20 mg/kg Tylosin were used in diets containing 16.5% and 14.0% of crude protein. The body weight of the animals averaged 46 kg (growing pigs) and 68 kg (finishing pigs).

In growing pigs the supplementation of Tylosin increased the digestibility of dry matter and energy at 1 percentage unit each, while in finishing pigs no effects were observed. Since the urinary energy excretion was not affected by antibiotics, there was only in Tylosin treated growing pigs a slight rise in dietary contents of metabolizable energy by 1.6%. The reduction of the dietary protein content resulted in increased digestibility of dry matter and energy, reduced urinary energy excretions and increased dietary contents of metabolizable energy.     

Effects of weaning age and formic acid-based feed additives on pigs from weaning to slaughter

Two hundred and forty piglets were used in a 2 x 6 factorial experiment to study the effects of weaning age (26 or 36 d) and four formic acid-based feed additives on the performance of pigs from weaning to slaughter. Either formic acid (F) or a mixture of formic acid, propionic acid, and potassium sorbate (FPS) or a mixture of formic acid, propionic acid, and sodium benzoate (FPB) or formic acid in a diatomaceous earth carrier (FD) were added to the diets of weaned piglets (from weaning to 60 d of age) and growing (18-46 kg) and finishing pigs (46-107 kg) to provide 8, 6, and 6 g acid per kg feed, respectively. The negative control treatment's (C) diets contained no growth promoters, whereas the positive control treatment's weaner and grower diets were supplemented with 40 mg/kg of avilamycin (A). The piglets weaned at the age of 26 and 36 d weighed 7.6 and 10.7 kg at weaning (p < 0.001), and 18.5 and 17.9 kg at the age of 60 d (p > 0.05), respectively. There was a weaning age x feed additive interaction in the weight gain of piglets after weaning (p < 0.05). The weight gain of piglets weaned on day 26 was enhanced by A, FPS, and FD (p < 0.05), and that of piglets weaned on day 36 by A and FPB (p < 0.05). The feed conversion ratio was not affected by weaning ages but was decreased in groups A, F, FBS, and FPB (p < 0.05). The severity of post-weaning diarrhoea was less in groups A, F, FPS, and FD than in C (p < 0.05). In piglets weaned on day 26, faecal water content and the total Escherichia coli count were highest 9 d after weaning. The total E. coli count was reduced only by FD (p < 0.05). Increased faecal water content was characterized by increased faecal Na+ and decreased K+ concentrations. Weaning age did not influence performance or carcass quality in the growing-finishing pigs. Feed additives did not affect weight gain in the growing pigs, but FPS and FPB enhanced weight gain during finishing period and total fattening (p < 0.05). In summary, the pigs' growth performance from weaning to slaughter was not affected by weaning age but it was enhanced by mixtures of formic and propionic acids with small amounts of sorbate or benzoate.     

Finishing season and feeding resources influence the quality of products from extensive-system Gascon pigs. Part 1: Carcass traits and quality of fresh loin

Consumers perceive pork products from local breeds reared in extensive systems positively because of their specific quality properties and regional identity. The sensory, nutritional and technological qualities of these products depend, among other things, on pig production, especially its climatic conditions and the availability of feed resources, which can influence traits of muscle and fat tissue. The present study (part 1) was part of a larger project that assessed the influence of the finishing season and feeding resources on carcass and tissue traits and the quality of meat and dry-cured ham from Gascon pigs in an extensive system. Following the specifications of the Protected Designation of Origin “Noir de Bigorre”, castrated Gascon males were reared on rangelands (grassland and forest areas) and received a supplementary diet from 5 to 6 months of age until slaughter at a minimum of 12 months of age and ca. 170 kg live weight. Three finishing seasons were considered as follows: Winter (n = 18), Spring (n = 22) and Autumn (n = 23). To estimate specific effects of season on productive and quality traits and avoid bias due to effects of genes known to influence these traits, polymorphisms in the RYR1, PRKAG3, MC4R and LEPR genes were included in the analysis models. The finishing season did not influence growth rate. Compared to Winter pigs, Spring and Autumn pigs had slightly lower carcass fatness (P < 0.05), higher ultimate pH and redder and darker color of the Longissimus muscle (LM) (P < 0.01). Loin drip loss was low overall, but was higher for Spring pigs, whereas cooking loss and shear force were similar among seasons. Spring pigs tended to have the lowest LM lipid content, whereas LM myoglobin content remained unaffected. Autumn pigs had lower potential of lipid oxidation in LM than Winter and Spring pigs (P < 0.01), but muscle metabolic traits assessed via glycolytic and oxidative enzyme activities did not differ among seasons. The finishing season modified the backfat fatty acid (FA) profile, with a lower polyunsaturated FA percentage in Autumn pigs than Winter or Spring pigs (P < 0.001), even though the saturated and monounsaturated FA percentages did not differ. In particular, Spring pigs had the lowest n-6:n-3 and C18:2:C18:3 ratios (P < 0.001), as a result of grazing. Overall, Spring and Autumn finishing seasons seem more favorable to technological and sensory pork attributes, with an additional positive effect of Spring finishing on pork nutritional value.     

The association of CAPN1 316 marker genotypes with growth and meat quality traits of steers finished on pasture

The objective of this paper was to determine the association of a SNP in the μ-calpain gene at position 316 with growth and quality of meat traits of steers grown on pasture. Fifty-nine Brangus and 20 Angus steers were genotyped for CAPN1 316. Warner Bratzler shear force was measured in l. lumborum samples after a 7-day aging period. A multivariate analysis of variance was performed, including shear force (WBSF), final weight (FW), average daily gain (ADG), backfat thickness (BFT), average monthly fat thickness gain (AMFTG), rib-eye area (REA), and beef rib-eye depth (RED) as dependent variables. The CAPN1 316 genotype was statistically significant. Univariate analyses were done with these variables. The marker genotype was statistically significant (p < 0.05) for WBSF (kg: CC: 4.41 ± 0.57; CG: 5.58 ± 0.20; GG: 6.29 ± 0.18), FW (kg: CC: 360.23 ± 14.71; CG: 381.34 ± 5.26; GG: 399.23 ± 4.68), and ADG (kg/d: CC: 0.675 ± 0.046; CG: 0.705 ± 0.016; GG: 0.765 ± 0.014) Shear force, final weight and average daily gain were significantly different according to the CAPN1 316 marker genotypes. The marker genotype was statistically significant in the multivariate analysis (p = 0.001). The first characteristic root explained 89% of the differences among genotypes. WBSF, FW and ADG were the most important traits in the first vector, indicating that animals with the marker genotype for lowest WBSF also have the lowest FW and ADG.     

The response of various muscle types to a restriction -re-alimentation feeding strategy in growing pigs

Muscle lipid concentration is known to influence pork eating quality. This study aimed at evaluating the effect of a restriction-re-alimentation feeding strategy on intramuscular fat deposition in pigs. A total of 70 Duroc × (Large White × Landrace) pigs (castrated males and females) were used. Ten pigs were first slaughtered at 30 kg live weight (LW) to determine initial body and muscle composition. From 30 to 80 kg LW (growing period), pigs were either fed ad libitum (AL) or restricted to 70% of the ad libitum intake of AL pigs (RA). From 80 to 110 kg LW (finishing period), both AL and RA pigs were fed ad libitum. In each group, pigs were slaughtered at 80 kg (n = 10) and at 110 kg (n = 20) LW. During the growing period, the growth rate of RA pigs was reduced by 30% (P < 0.001) compared with AL pigs. During the finishing period, RA pigs had a 7% (P = 0.09) higher growth rate than AL pigs due to compensatory feed intake (+14%). Plasma insulin-like growth factor-1 concentration was lower in RA pigs at 80 kg LW, but markedly increased after re-alimentation up to the level observed in AL pigs (P < 0.001). At 80 kg, the leaner carcasses of RA pigs resulted from a more pronounced reduction in fat than in lean tissue deposition rates. Re-alimentation of RA pigs increased fat tissue deposition (+160% for females, P < 0.01) but not lean deposition in the carcass, leading to limited differences in carcass composition between RA and AL pigs at 110 kg LW. Regarding tissue deposition rates, the response to feeding strategy differs between muscles. In the m. biceps femoris (BF), restriction affected lipid (-50%, P < 0.001) and protein (-25%, P < 0.001) deposition, whereas re-alimentation increased lipid (+62%, P < 0.05) but not protein deposition rates. At market weight, the extent of the difference in BF lipid concentration between RA and AL pigs was strongly reduced, but still significant. By contrast, in the m. longissimus, restriction decreased protein but not lipid deposition, whereas neither of them was modified during re-alimentation. Therefore, an increased muscle lipid concentration at 110 kg LW could not be reached in RA pigs. Modifications of onset and/or duration of restriction and re-alimentation periods should be tested to optimise effects on muscle lipid deposition and thereby achieve improved pork quality.     

Nicotine stimulates prolactin-releasing peptide (PrRP) cells and non-PrRP cells in the solitary nucleus

Nicotine has been reported to regulate food intake and body weight. But the mechanisms underlying these roles have not been fully elucidated. In the present study, we showed that acute administration of nicotine (0.5 mg/kg s.c.) could activate prolactin-releasing peptide (PrRP)-bearing neurons in the A2 area of the NTS of rats, suggesting that PrRP may be associated with nicotine-induced effects in the central nervous system (CNS). We next treated rats with nicotine chronically (4 mg/kg/day for 7 days i.p.), and the results showed that the body weight was strongly reduced and food intake was greatly suppressed compared to the vehicle control group (p<0.01). Immunocytochemical studies revealed that PrRP-bearing neurons in the NTS were evidently activated after chronic administration of nicotine, suggesting that PrRP was involved in the regulation of nicotine-mediated body weight loss and food intake suppression in rats. We also found that acute/chronic administration of nicotine activated PrRP-negative neurons in the NTS, and the majority of these neurons were shown to be TH-negative, suggesting that noncatecholaminergic, PrRP-negative neurons in the NTS are associated with the roles of nicotine. Nicotine has also been shown to stimulate the secretion of ACTH, a stress responsive hormone. In the present study, rats received nicotine (0.5 mg/kg s.c.) or saline followed by restraint stress for 30 min. The immunocytochemical results showed that nicotine/stress and saline/stress both activated the majority of the PrRP neurons in the NTS, there being no significant difference between the two treatments (p>0.05). Nicotine/stress also greatly activated PrRP/TH-negative neurons in the NTS. Saline/stress, however, caused much lower effect on the activation of PrRP/TH-negative neurons. In addition, the activation effect of nicotine/stress on PrRP/TH-negative neurons was much stronger than that of nicotine alone (p<0.01). These results indicated that PrRP was associated with stress responses, but it had little effect on nicotine-mediated stress responses. On the other hand, nicotine and restraint stress may synergistically activate PrRP/TH-negative neurons in the NTS. Taken together, our data show that PrRP is involved in the nicotine-induced regulation of body weight and food intake, but may not be involved in the mediation of nicotine on stress responses. PrRP/TH-negative neurons in the NTS are also associated with the roles of nicotine in the CNS.     

Effects of fermented oyster mushroom ( Pleurotus ostreats) by-product supplementation on growth performance, blood parameters and meat quality in finishing Berkshire pigs

The objective of the present study was to investigate the effects of fermented oyster mushroom (Pleurotus ostreats) by-production (FOMP) supplementation on the growth performance, blood parameters, carcass traits and meat quality in finishing Berkshire pigs. FOMP was made by mixing oyster mushroom by-production with rice bran and barley bran and this mixture was fermented for 60 days. The experimental diets were 0, 3, 5 and 7% of FOMP added to C, T1, T2 and T3 in the basis diet for 7 weeks. Average daily gain (kg/day) was higher in C and T1 than in T2 and T3 ( P < 0.05). Average daily feed intake (kg/day) and feed conversion increased by the addition of FOMP ( P < 0.05). Total cholesterol and high-density lipoprotein cholesterol were higher in T3 than other treatments ( P < 0.05). Carcass weight (kg) was higher in C and T1 than in T2 and T3 ( P < 0.05). Dressing (%) was higher in C than in T3 ( P < 0.05). Crude protein was lower in T3 than in other treatments ( P < 0.05). Crude fat was higher in T2 and T3 than in C ( P < 0.05). pH₂₄ was higher in C than in other treatments ( P < 0.05). Cooking loss (%) was higher in T1 than T2 ( P < 0.05). Water-holding capacity (%) was higher in C than in T1 ( P < 0.05). In meat colour, CIE a* was lower by the addition of FOMP ( P < 0.05). CIE b* was higher in C than in other treatments ( P < 0.05). In backfat colour, CIE L* was lower in T3 than other treatments ( P < 0.05). CIE b* was lower by addition of FOMP ( P < 0.05). Palmitoleic and oleic acid were higher in T3 than in other treatments ( P < 0.05). Linoleic and arachidonic acids were higher in T2 than in other treatments ( P < 0.05). The results indicate that 3% of FOMP affected the growth performance, carcass traits, meat quality and fatty acid in contrast to addition of 5% of FOMP for Berkshire pigs during the finishing period.     

Manganese alters mitochodrial integrity in the hearts of swine marginally deficient in magnesium

It was previously reported that pigs marginally deficient in magnesium (Mg) and fed diets high in manganese (Mn) died suddenly with signs of sudden cardiac death. Manganese, which has properties similar to Mg, may exacerbate Mg-deficiency and be accumulated by mitochondria resulting in ultrastructural damage. The objective of this study was to determine whether deaths of the type previously observed were mediated by adverse interactions of Mn and Mg resulting in ultrastructural damage to the myocardium, alterations in electrocardiographic recordings and tissue retention of Mn, Mg and calcium (Ca). Forty-eight pigs were fed one of six diets in a 2 X 3 factorial arrangement of Mg (100 or 1000 mg Mg/kg) and Mn (5, 50 or 500 mg Mn/kg) for 8 weeks. Left ventricle muscle samples were collected for examination by transmission electron microscopy. No differences in heart muscle ultrastructure were observed between pigs fed low and adequate dietary Mg. However, marked myocardial necrosis and mitochondrial swelling were observed in pigs fed high dietary Mn when combined with low Mg. Feeding low dietary Mg elevated minimum (P < 0.01), maximum (P < 0.05) and average (P < 0.001) heart rates. Low dietary Mg resulted in a 55% probability of a ventricular beat being recorded (P = 0.05) and lower Mg (P < 0.02) and Ca (P < 0.04) contents in heart atria and ventricles. These results suggest that high Mn, when fed in combination with low Mg, disrupts mitochondrial ultrastructure and is associated with the sudden deaths previously reported.     

Effects of dietary amylose and amylopectin ratio on growth performance,meat quality,postmortem glycolysis and muscle fibre type transformation of finishing pigs

The present study was conducted to investigate the effects of dietary amylose and amylopectin ratio on growth performance, meat quality, postmortem glycolysis and muscle fibre type transformation of finishing pigs. Twenty-four barrows (Duroc × Landrace × Yorkshire) with an average initial body weight of 61.7 ± 2.01 kg were randomly assigned to four dietary treatments with amylose: amylopectin ratios of 1:1 (HD), 1:2 (MD), 1:3 (CD) and 1:4 (LD). The results showed that the average daily weight gain of finishing pigs tended to reduce with the ratio of amylose and amylopectin decreased (p = 0.09). Diet LD increased the pH_24h value and decreased the shear force in longissimus dorsi (LM) compared with diet HD (p < 0.05). Diet LD decreased the lactate content and the HK-2 mRNA abundance and increased the mRNA abundance of ATP5B in LM compared with diet HD (p < 0.05). Higher mRNA abundance of MyHC I and lesser abundance of MyHC IIb in LM were found in pigs fed diet CD and LD than those fed diet HD (p < 0.05). Furthermore, pigs fed diet LD had higher mRNA abundances of PGC-1α and PPAR δ in LM than other groups (p < 0.05). These results suggested that diet with low amylose and amylopectin ratio could improve meat quality of finishing pigs via delaying muscle glycolysis capacity and shifting muscle fibre types.     

Efficacy of virginiamycin and a commercially-available lactobacillus probiotic in swine diets

Eight feeding trials using 708 cross-bred pigs were conducted to evaluate the addition of virginiamycin and a commercially-available lactobacillus fermention product (probiotic) to starter, grower and finisher diets based on maize and soya bean meal. Virginiamycin was added at a level of 11 mg/kg of diet, and lactobacillus probiotic at 1 g/kg in starter diets and 500 mg/kg in grower and finisher diets. In the combined analysis of four starter trials, pigs fed on diets containing virginiamycin tended to eat more and grow faster than pigs fed on the control diet, but feed efficiency was not different. Furthermore, daily gain, daily feed intake and feed efficiency were not improved by the addition of lactobacillus probiotic to starter diets. In the combined analysis of a starter—grower—finisher and a grower—finisher trial, virginiamycin supplementation did not alter overall pig performance compared with control. Pigs fed on a positive control diet containing chlortetracycline, penicillin and sulfamethazine had a nonsignificantly greater daily gain and feed intake.Daily gain for the lactobacillus probiotic-fed pigs was lower (P < 0.05) than that of the negative controls, but daily feed intake and feed efficiency were not significantly different. In three growing—finishing trials in which virginiamycin and lactobacillus probiotic were compared in a 2 × 2 factorial arrangement of treatments, daily gain and feed intakes were greater (P < 0.01) for pigs given virginiamycin. The lactobacillus probiotic did not improve daily gain, feed intake or feed efficiency. Overall, no interaction between virginiamycin and lactobacillus probiotic occurred.     

Free radical scavenging activity of Lactobacillus fermentum in vitro and its antioxidative effect on growing–finishing pigs

Aims:  To evaluate the free radical-scavenging capacity of Lactobacillus fermentum and its effects on antioxidant enzyme levels in finishing pigs.
Methods and Results:  The free radical-scavenging activity of Lact. fermentum was analysed in vitro . The tested Lactobacillus showed a high scavenging ability against DPPH (1,1-diphenyl-2-picrylhydrazyl), superoxide and hydroxyl radicals which was dose dependent. Subsequently, 108 crossbred pigs weighing 20·67 BW, were allotted to dietary treatments including a basal diet or the basal diet supplemented with either aureomycin or 10·2 × 10⁷  Lact. fermentum CFU g⁻¹ diet. Supplementation of Lact. fermentum increased total antioxidant capacity ( P  < 0·01) in serum from 50 kg pigs, while serum superoxide dismutase ( P  = 0·01) and glutathione peroxidase ( P  < 0·01) increased, and malondialdehyde levels decreased ( P  < 0·01) in 90 kg pigs. Hepatic catalase ( P  = 0·04), muscle superoxide dismutase ( P  < 0·01) and copper–zinc-superoxide dismutase were enhanced ( P  = 0·01), whereas malondialdehyde levels were reduced ( P  = 0·05) by Lact. fermentum .
Conclusions:  The free radical-scavenging capacity of Lact. fermentum was dose dependent and its supplementation improved the antioxidant status of pigs.
Significance and Impact of the Study:  Lactobacillus fermentum could be used to alleviate oxidative stress and increase pig performance and improve pork quality.     

Effect of dietary supplementation with different sources of selenium on growth response, selenium blood levels and meat quality of intensively finished Charolais young bulls

The study aimed at comparing three strategies of supplementing selenium (Se) during the finishing period of Charolais young bulls: (1) administration of sodium selenite throughout the finishing (NaSe); (2) administration of an Se-enriched yeast strain (Saccharomyces cerevisiae NCYC R397) throughout the finishing (Se-Y); (3) administration of sodium selenite for 140 days replaced by Se-enriched yeast during the last 70 days of finishing (Switch). Eighty-four young bulls (mean initial BW=434.2±31.9 kg; mean age=382±52 days) were stratified by live weight and equally assigned to one of three Se treatments. Experimental groups were fed the same diets and the inclusion rate of the different treatments was targeted to achieve 0.3 mg of Se/kg of dry matter (DM) in the complete feed. The average daily gain of bulls was 1.36 kg/d and no differences due to Se treatment were recorded. Dry matter intake and feed conversion ratio were not affected by Se treatment resulting in, on average, 10.3 kg/d and 7.65, respectively. Repeated blood samples were taken at days 0, 120, 180 and 210 of finishing to assess the Se status of the animals. As compared to NaSe, both organic Se treatments (Se-Y and Switch) increased plasma Se in the last two sampling sessions according to a significant treatment×time interaction (P<0.001). A similar trend was observed for serum total antioxidant status of the young bulls, whereas there was only a significant time effect (P<0.001) on glutathione peroxidase activity that was raised by all Se treatments. The finishing period lasted 210 days and at the abattoir there were no differences across Se treatments in carcass weight and dressing percentage. A higher Se content in the Longissimus thoracis (LT) muscle was instead observed in Se-Y samples as compared with NaSe (0.85 v. 0.47 mg/kg DM; P<0.05). Meat quality evaluation was carried out on LT samples after 6 and 11 days of ageing under a vacuum package. Regardless of ageing time, meat from young bulls supplemented with Se yeast had higher colour lightness (L*) values than those receiving NaSe (38.1 v. 36.6; P<0.01) and showed a significant decrease in shear force (3.69 v. 4.22 kg/cm2; P<0.01). The outcomes of the study suggest that the provision of Se yeast throughout the finishing period is a strategy to increase the benefits of the replacement of sodium selenite with organic selenium in beef cattle.     

Effect of excessive dietary fluoride on nutrient digestibility and retention of iron, copper, zinc, and manganese in growing pigs

Ninety-six crossbred growing pigs were used to evaluate the effects of fluoride levels on growth performance, nutrient digestibility, and the retention of minerals in tissues. Four dietary treatments were formulated by supplementing fluorine (as NaF) to a corn-soybean basal diet (39.75 mg/kg F) to provide the following added fluorine levels: 0, 50 100, and 150 mg/kg fluorine. The results showed pigs of the 100 and 150 mg/kg fluorine-added groups had decreased average daily gain (ADG) and increased feed gain ratio (F/G) compared to the control (p<0.05). Apparent digestibility of protein and calcium in 100 and 150 mg/kg fluorinetreated groups was significantly lower than that of the control (p<0.05). On the other hand, iron, copper, zinc, and manganese levels in most tissues of the 100 and 150 mg/kg fluorine groups were markedly changed compared to the control (p<0.05). However, growth performance, nutrient digestibility, and mineral concentrations in all tissues of pigs were not significantly affected by the addition of 50 mg/kg fluorine (p>0.05). Thus, this study suggested that excess fluoride levels could decrease growth performance and change the retention of iron, copper, zinc, and manganese in pigs.