Veterinary Toxicovigilance: Objectives,Means and Organisation in France

Veterinary Research Communications -     

Energy utilization of sodium hydroxide treated or untreated straw supplemented with protein or concentrates by adult sheep. 2. Rumen digestion

NaOH treated (T) or untreated (UT) barley straws were supplemented either with protein (P) or with concentrates based on maize (M) or beet pulp (BP), the two last at rates of 25 and 50% of the diet. Each of the 10 diets was fed to two sheep ad libitum. Two diets were also fed at limited intakes. For these 12 diets in sacco cellulolytic activity in the rumen and ruminal fermentation were measured. Cellulolytic activity was measured with the studied straws, so that their digestion rate was also determined. NaOH treatment increased rate of digestion of straw, while high levels of concentrates decreased it. In contrast NaOH treatment and high levels of concentrate decreased cellulolytic activity but neither type of concentrate nor limitation of intake altered it. NaOH treatment only slightly modified pH because a higher level of VFA in rumen balanced NaOH presence. An important negative effect on pH of high levels of concentrate was observed, but there was no effect or type of concentrate or limitation of intake. Fermentation pattern was only slightly influenced by studied factors: +2.2 units of butyric acid and -2.1 units of acetic acid with treated straw; lower level of acetic acid occurred when concentrate was increased, especially for maize. Limitation of intake increased acetic acid molar proportion.     

Energy utilization of two diets for maintenance by horses; agreement with the new French net energy system

Four Standardbred geldings were fed hay or a diet of 60% hay + 40% concentrate at 2 levels of feeding. Feces and urine were collected for 6 days. Energy balances were determined by indirect calorimetry for4 days. The metabo- lizable energy (ME) requirements for maintenance of horses were calculated as ME intake for zero energy gain. They averaged 151 + 14 and 132 + 10 kcal/kg W -Ts for the hay diet and the mixed diet, respectively. The 14% difference in efficiency of ME utilization for maintenance predicted by the new French net energy system.     

Energy utilization of two diets for maintenance by horses; agreement with the new french net energy system

Four Standardbred geldings were fed hay or a diet of 60% hay + 40% concentrate at 2 levels of feeding. Feces and urine were collected for 6 days. Energy balances were determined by indirect calorimetry for 4 days. The metabolizable energy (ME) requirements for maintenance of horses were calculated as ME intake for zero energy gain. They averaged 151 ± 14 and 132±10 kcal/kg W^.75 for the hay diet and the mixed diet, respectively. The 14% difference in efficiency of ME utilization for maintenance predicted by the new French net energy system.     

Ryegrass-based diet and barley supplementation: partition of energy-yielding nutrients among splanchnic tissues and hind limbs in finishing lambs

Splanchnic metabolism of energy-yielding nutrients and their uptake by the hind limb were studied in finishing lambs receiving ryegrass harvested at grazing stage (ear at 10 cm) with or without barley supplementation. Six ruminally cannulated and multicatherized lambs (40.2 +/- 1.5 kg) were fed with frozen ryegrass (RG) at 690 kJ of metabolizable energy intake (MEI) x d(-1) x BW(-0.75) successively with and without barley supplementation (RG + B), according to a triplicated Latin square design. Barley supplementation represented 21% of DM intake and increased the MEI by 32% (P < 0.002). In ruminal fluid, barley supplementation increased the acetate and butyrate concentrations by 21.2 and 49.6%, respectively (P < 0.04), without modifying those of propionate. Thus, molar proportions of acetate and butyrate were not modified, and those of propionate tended (P < 0.06) to decrease from 26 to 23%. As a result, the net portal appearance of propionate was not modified. Net portal appearance of butyrate and beta-hydroxybutyrate increased (P < 0.03), and that of acetate was not modified. Consequently, hepatic uptake of butyrate increased and probably spared acetate from hepatic metabolism. The hepatic fractional extraction of propionate decreased (P < 0.03), whereas the net flux of lactate switched from a net release to a net uptake, suggesting an alteration in the contribution of gluconeogenic substrates to glucose synthesis without modification in net hepatic glucose release. As a consequence, barley supplementation increased net splanchnic release of acetate (P < 0.02), propionate (P < 0.001), and beta-hydroxybutyrate (P < 0.01) by 60, 157, and 78%, respectively. In addition, the net splanchnic release of insulin increased (P < 0.03) because of a decrease (P < 0.02) in its hepatic extraction. Despite those changes, the net uptake of nutrients by the hind limb was not modified and even decreased in the case of glucose (P < 0.02), suggesting a stimulation of lipogenesis in adipose tissues. Results from the present study suggested that supplementation of a ryegrass-based diet would likely have little effect on the orientation of muscle energy metabolism and on meat quality because the net uptake of nutrients by the hind limb was unchanged.     

Energy utilization of sodium hydroxide treated or untreated straw supplemented with protein or concentrates by adult sheep. 1. Feed intake, digestibility, metabolizability and net energy value

NaOH treated (T) or untreated (UT) barley straws were supplemented either with protein (P) or with concentrates based on maize (M) or beet pulp (BP) at rates of 25 or 50% of the diet. Each of the 8 diets was fed to 8 sheep near ad libitum and near maintenance. Energy balances were determined by indirect calorimetry. Straw and feed intakes were doubled by the alkali treatment (P, BP25 and BP50 diets) or increased by 83% (M25 diet) and 63% (M50 diet). Near maintenance, energy digestibility (dE) and metabolizability (q) of the straw were improved by 36% and 40% respectively in the P diet and by 28% and 25% on average in the other diets. Ad libitum feeding reduced energy digestibility of treated straw by 11% and metabolizability by 5% on average in the BP25, BP50 and M25 diets; in the case of the M50 diet dE of the T straw was depressed by 30% and the beneficial effect of the alkali treatment was suppressed. The efficiency of metabolizable energy (ME) of the treated straw diets for maintenance was also raised by 9% (P diet) to 3% (M50 diet) and the corresponding net energy content of the treated straw was increased by 58 to 30%. ME efficiencies of the diets for fattening ranged from 44.0 to 52.8%. Energy retention of sheep was considerably increased by the alkali treatment of straw, whereas their maintenance requirement could not be met by the untreated straw diets supplemented with 25% concentrate.     

Maintenance energy requirement variations determined by indirect calorimetry and feeding trials in light horses

Ten Standardbred horses were fed a mixed diet (60% hay + 40% concentrate) at a maintenance and 1.2 times maintenance over 2 three-month-periods in winter and summer feeding trials. Energy expenditure was measured also by indirect calorimetry in 4 of these horses. The DE and ME requirements for maintenance were calculated for zero energy gain in both cases. Energy requirements measured by feeding trial and by indirect calorimetry were consistent: 129 ± 10 and 132 ± 10 kcal ME/W^0.75.Ts respectively. Individnal variability of requirements was 8% in both methods. ME requirements were 9% higher in summer than in winter and difference between young and adult horses ranged from −3% to +11%.