Effect of grazing pastures of different botanical composition on antioxidant enzyme activities and oxidative stability of lamb meat.

The aim of this work was to study the influence of different pastures (Intensive ryegrass, Botanically diverse and Leguminosa rich pastures) on the antioxidant status and oxidative stability of meat from lambs that had been exclusively grazing for three months. Lipid, colour and protein oxidation, α-tocopherol content and activity of antioxidant enzymes (superoxide dismutase (SOD), catalase (Cat) and glutathione peroxidase (GSH-Px)) were measured in Longisimus thoracis et lumborum muscle samples taken 1 day after slaughter. Pasture type significantly affected protein oxidation and the activity of GSH-Px, but no significant differences were found for the α-tocopherol content, colour and lipid oxidation, and the activities of SOD and Cat. Grazing a Botanically diverse pasture induced significantly higher protein oxidation in meat, as measured by the free thiol and carbonyl contents, compared to a Leguminosa rich or Intensive ryegrass pasture (P<0.05). The GSH-Px activity was significantly higher in meat from lambs on the Leguminosa rich pasture compared to the other pasture groups (P<0.01).

Immunocastrated male pigs: effect of 4 v. 6 weeks time post second injection on performance, carcass quality and meat quality.

Immunocastration or vaccination against boar taint can be used as alternative for surgical castration of male piglets. The vaccine is administrated twice. After the second vaccination (V2), the pigs behave like barrows instead of boars and their feed intake increases which may result in a lower lean meat percentage. The timing of V2 is therefore crucial to find the right balance between the advantages of entire males and barrows. In this study, we evaluated the effect of time post second injection within the advised time frame (4 v. 6 weeks before slaughter) on behaviour, performance, carcass and meat quality of immunocastrated male pigs. In total, 180 animals (hybrid sow×Piétrain): 60 gilts, 60 male pigs vaccinated 6 weeks before slaughter (IM-6) and 60 male pigs vaccinated 4 weeks before slaughter (IM-4), all slaughtered at comparable slaughter weights. After 20 weeks of age, IM-6 showed more inactive behaviour at the expense of playing and aggressive behaviour. Daily feed intake (DFI), daily gain (DG) and feed conversion ratio (FCR) did not differ significantly between IM-6 and IM-4. Gilts had a lower DFI and DG in the late finishing phase and a higher FCR overall compared with both IM groups. Gilts showed a higher lean meat content compared with both IM groups. Earlier vaccination increased dressing percentage, which could partly be explained by the lower weight of the gastrointestinal tract, but not by testes weight. Meat quality traits and palatability did not differ significantly between IM-6 and IM-4. Vaccination of immunocastrates at 6 compared with 4 weeks before slaughter improved the calmness in the stable and the dressing percentage, while maintaining performance and carcass characteristics.

Differences in susceptibility of winter wheat varieties for Fusarium species under Belgian growing conditions.

Fusarium head blight is an important disease of cereal crops caused by Fusarium species. It causes not only a reduction in yield, but most Fusarium species (F. graminearum. F. culmorum, F. avenaceum. F. poae) produce also a range of toxic metabolites such as deoxynivalenol (DON) and zearalenone (ZEA). The evaluation of Fusarium species was followed up under natural infection conditions during the growing seasons 2001--2002 and 2002--2003 in two varietal winter wheat experiments on the experimental farm of the Hogeschool Gent at Bottelare. Disease pressure, DON and ZEA content, different Fusarium species as well as growth and yield parameters were determined. In both years there were significant differences between the varieties concerning the susceptibility to Fusarium and the DON content. ZEA was not found in the kernels. The mean deoxynivalenol (DON) content was in 2002 (1,126 mg/kg) higher than in 2003 (0.879 mg/kg) although the mean disease severity was bigger in 2003 than in 2002 what means that the DON content was not always correlated with the disease severity. The Fusarium species most frequently identified in our two field trials (Bottelare) were F. graminearum and F. culmorum Varietal differences in susceptibility to Fusarium species and DON contamination could be detected.

Supplementing salinomycin to diets for growing-finishing pigs.

Feeding experiments with growing-finishing pigs were carried out to study the effect of different dietary salinomycin concentrations upon animal performance. Besides a dietary treatment without antibiotic, three treatments consisted of 20/10 mg/kg, 40/20 mg/kg and 60/30 mg/kg salinomycin (the first and second number refer to the salinomycin content in grower and finisher diet, respectively). Compared to the control group, feeding diets with 20 or 40 mg/kg salinomycin resulted in significantly higher weight gain in the grower period (25-45 kg body weight), while also feed conversion was lower (although not statistically significant). In the finisher period (45-100 kg body weight) salinomycin had no significant effect upon weight gain or feed conversion efficiency, but the 20 and 30 mg/kg treatments yielded the best results. Considering the grower and finisher period together the dietary treatments 40/20 mg/kg and 60/30 mg/kg showed highest growth rate and most favourable feed conversion, although not statistically significant. Carcass characteristics (dressing percentage, carcass length, backfat thickness, percent meat) were not affected by dietary salinomycin supplementation.

Flavomycin effects on performance of beef bulls and nutrient digestibility in wethers.

For 28 weeks a feeding experiment was conducted to determine the effects of dietary flavomycin on performance of beef bulls. In the first and second half of the trial, 40 animals (average initial weight 352 kg) had free access to corn silage or beet pulp, respectively, both supplemented with an appropriate concentrate containing 0 or 10 mg/kg of the antibiotic. Daily flavomycin intake was 39 to 46 mg when the animals were on the corn silage diet and 51 to 54 mg when they were fed the beet pulp diet. The animals fed the corn silage-based diet supplemented with flavomycin showed a non-significant improvement of daily gain (1.4%) and feed conversion (2.3%). When the beet pulp-based diet was fed, flavomycin significantly increased daily gain (15.2%, P less than 0.002) and feed conversion efficiency (9.1%, P less than 0.03). For the overall feeding experiment the positive effect of flavomycin feeding was 6.7% on body weight gain (P less than 0.09) and 5.2% on feed conversion (P less than 0.13). Flavomycin did not affect carcass yield of beef bulls. Also the effect of flavomycin on diet digestibility was studied in wethers fed a mixture of beet pulp and concentrate, containing 0 or 10 ppm flavomycin. No significant effect from the antibiotic on digestion of dry matter, crude protein, fibre, fat, ash and N-free extract was observed.

Influence of a marine algae supplementation on the oxidative status of plasma in dairy cows during the periparturient period.

This study was part of a larger study that addressed the effects of marine algae (ALG) supplementation in the ration of high yielding periparturient dairy cows. The objectives were to induce milk fat depression (MFD) in early lactation by feeding docosahexaenoic acid (DHA) from ALG and to determine the effects on milk production, milk components and metabolic status early post partum. This study focuses on the oxidative status in the plasma during the ALG supplementation. Plasma samples were collected from 16 Holstein Friesian cows at the day of parturition and at -1, 2, 4 and 6 weeks relative to calving with half of the cows receiving the ALG supplement (44gDHA/d) from 3 weeks pre partum on. The following parameters were measured in plasma: ferric reducing ability of plasma (FRAP), α-tocopherol level, glutathione peroxidase activity (GSH-Px) and thiobarbituric acid reactive substances (TBARS) concentration. There was a significant effect of time for FRAP and α-tocopherol indicating changes in the plasma oxidative status around parturition. The ALG supplementation was successful in creating a milk fat depression (MFD) but could not improve the energy balance. Feeding of ALG significantly increased lipid peroxidation as measured by TBARS, probably through their high content of n-3 polyunsaturated fatty acids.

Fatty acid profile and oxidative stability of pork as influenced by duration and time of dietary linseed or fish oil supplementation.

In this experiment, the effect of duration and time of feeding n-3 PUFA sources on the fatty acid composition and oxidative stability of the longissimus thoracis (LT) muscle was investigated. Linseed (L) and fish oil (F), rich in alpha-linolenic acid and eicosapentaenoic and docosahexaenoic acid (EPA and DHA), respectively, were supplied equivalent to a level of 1.2% oil (as fed), either during the whole fattening period or only during the first (P1; 8 wk) or second (P2; 6 to 9 wk until slaughter) fattening phase. All diets were based on barley, wheat, and soybean meal and were fed ad libitum. Crossbred pigs (n = 154; Topigs 40 x Piétrain) were randomly allotted to the 7 feeding groups. In the basal diet (B), only animal fat was used as the supplementary fat source. Three dietary groups were supplied the same fatty acid source during both fattening phases (i.e., group BB, LL, and FF). For the other 4 dietary groups, the fatty acid source was switched after the first phase (groups BL, BF, LF, and FL; the first and second letter indicating the diet in P1 and P2, respectively). Twelve animals per feeding group were selected based on average live BW. The LT was analyzed for fatty acid composition; lipid stability (thiobarbituric acid-reactive substances) and color stability (a* value, % of myoglobin pigments) were determined on the LT after illuminated chill storage for up to 8 d. The alpha-linolenic acid, EPA, and docosapentaenoic acid incorporation was independent of the duration of linseed feeding (1.24, 0.54, and 0.75% of total fatty acids, respectively, for group LL). Supplying fish oil during both phases resulted in the greatest EPA and DHA proportions (1.37 and 1.02% of total fatty acids; P < 0.05), but the content of docosapentaenoic acid was not affected. The proportion of DHA was greater when fish oil was administered during P2 compared with P1 (P < 0.05). There was no effect of diet on meat ultimate pH and drip loss or on lipid or color oxidation.

Cholesterol-lowering effects and utilization of protein, lipid, fiber and energy in rats fed unprocessed and baked oat bran.

The effects of the addition of 15% or 30% non-heated oat bran or 30% baked oat bran to a purified diet on apparent digestibility of dry matter, protein, lipid and fiber were measured in balance experiments with male Wistar rats. The effects of oat bran on dietary metabolizable energy, fecal bulking capacity and transit time of the ingested food were also studied. Heat processing of oat bran occurred in conditions of moisture and temperature similar to those of bread baking. Compared with the unprocessed oat bran, the baked product had a higher content of insoluble fiber, mainly due to higher Klason lignin content and a shift from soluble to insoluble beta-glucans. Relative to the fiber-free control diet, feeding the oat bran diets increased wet and dry fecal weight and decreased the transit time of the food. Fecal bulking capacity increased proportionally with oat fiber intake. Metabolizable energy of the diets, as well as apparent digestibility of dry matter and protein decreased with oat bran supplementation; on the other hand, lipid digestibility was not significantly changed. Baking of oat brain resulted in no statistically significant effects on dietary metabolizable energy or apparent digestibility of dry matter, protein, lipid and fiber. The measured metabolizable energy of oat bran ranged between 12.7 and 13.2 MJ/kg. Total plasma cholesterol concentration diminished with oat brain intake; non-heated and baked oat bran had comparable effects on plasma cholesterol. An inverse linear relationship (r = -0.80, P less than 0.1) was found between plasma cholesterol concentration and fecal excretion of bile acids.