Livio Magni

Effect of prolonged branched-chain amino acid supplementation on metabolic response to anaerobic exercise in standardbreds

Summary This study investigated the effect of prolonged BCAA supplementation on metabolic response to a 1600m run on treadmill in Standardbred trotters. Four trained Standardbreds were divided into two groups and assigned in a 2×2 Latin square design. Both groups were fed and exercised similarly: one group received an oral amino acids supplement (12 g leucine, 9 g isoleucine and 9 g valine) 30 minutes prior to exercise and immediately after, the other group received a placebo. The horses received the supplement 3 days per week for 5 weeks. In the last week horses performed an anaerobic exercise test on an inclined (3.5%) high-speed treadmill. The exercise consisted of a 15 minute warm-up phase immediately followed by a 1600 m run at maximal speed (heart rate > 200 beats/min). Blood samples were collected pre-exercise, after exercise and during recovery (10 min, 30 min, and 24 h), and analyzed for lactate, ammonia, total protein, urea, uric acid, creatinine, free fatty acids (FFA), creatine kinase (CK), lactate dehydrogenase (LDH), aspartate amino transferase (AST). Heart rate was continuously recorded during exercise and recovery. No statistical differences between the groups were observed for all the considered parameters. Nevertheless, BCAA supplementation resulted in a higher plasma ammonia and urea concentrations as reported in previous studies in humans and rats. These data suggest that a BCAA supplementation are not effective in enhancing performance in healthy and well-fed horses.

Total mixed ration in exercising horse: digestibility and nitrogen metabolism

Abstract The aim of this study was to evaluate the apparent digestibility of a total mixed ration (TMR) versus a traditional mixed hay/cereals diet. Four adult trained Standardbred geldings – BW = 478±37 kg - were used. The two diets consisted of 20 kg of a commercial TMR - corn silage, alfalfa hay, wet brewers’ grain, oat, apple pomace, molasses cane, soybean oil and mineral/vitamin supplement - (Diet 1) or 7 kg of meadow hay and 4.5 kg of cereal-mix - corn, oat, barley and protein/mineral/vitamin supplement - (Diet 2). The trial was conducted according to a Latin Square design (2x2). After an adaptation period of four weeks, total faeces and urine were collected for 6 days. Both feed and faeces samples were analysed for DM, OM, CP, EE, CF, NDF, ADF, cellulose, hemicellulose, ADL and GE. Data were analysed by ANOVA. The apparent digestibility and nitrogen balance of the two diets were compared. DM, OM, CP and GE apparent digestibility were significantly different between the diets, with higher values for unifeed diet than traditional diet. Energy requirement was satisfied by both diets (96.54 vs 95.55 MJ). Nitrogen balance showed negative values in both diets (- 61.67 vs - 9.05), but the hay/cereals supplemented diet showed the best protein utilisation.

Apparent digestibility of three diets in the Amiata breed donkey during lactation

Abstract The aim of the trial was to evaluate the apparent digestibility of three isonitrogenous and isocaloric diets for lactating donkeys: a diet with 8 kg of hay and 1.5 kg of commercial flaked mixed feed (CM) (Diet 1); a diet with 7 kg of hay and a 2.2 kg of CM (Diet 2) and a diet with 7 kg of hay, 1.5 kg of CM, 200 ml of corn oil and 0.2 kg of soybean meal (Diet 3). Four pluriparous donkeys (309±12 kg BW) at approximately 2-4 months of lactation were used. The trial was conducted according to a 3x3 Latin Square design with 1 or 2 subject per each cell. Feed and faeces samples were analysed for DM, OM, CP, EE, CF, NDF, ADF and gross energy. Acid insoluble ash was used as marker to calculate the apparent digestibility. The apparent digestibility of the main dietary components showed not significant differences among the three diets but generally they were lower in Diet 3. DM intakes of every diet exceeded the estimated energy requirement, whereas protein requirements were not significantly satisfied by Diet 1.

Effect of different oils administration on oleic and linoleic serum profile in horses during standardised exercise test on treadmill

Abstract Because of its energy density, fat is often added to the diet for exercising horses; however, little attention has been given to the effect of dietary fatty acid composition. The aims of this study were to compare the effect of two diets containing different oils on the fatty acids haematic profile during and after an aerobic exercise test on treadmill. Four adult trained gelding Standardbred (mean BW=481±27 kg) were used in a two replicated 2x2 Latin Square design. Mixed hay-concentrate diets contained corn oil (CORN) or a mix of mono-di and triglycerides of olive oil (MDTO) were administrated. The horses received the diets for a period of four weeks. At the end of the adaptation period an aerobic exercise test on treadmill (30-min long) was carried on. Blood samples were collected at rest, after 15’ and 30’ of exercise and during recovery period (at 10’, 30’ and 60’). Serum fatty acid concentration was determined. MDTO supplemented horses showed an higher percentage of Oleic acid during and after the exercise test; whereas Linoleic acid showed a significant difference (P<0.05) between groups with the highest value at 10’ and 30’ after exercise in the CORN supplemented group.