No abstract

The synthesis of optically active (R)-2-trimethylsilyl-2-hydroxyl-ethylcyanide by asymmetric trans-cyanation of acetyltrimethylsilane with acetone cyanohydrin in a biphasic system was achieved using (R)-oxynitrilase from loquat seed meal. Diisopropyl ether was the most suitable organic phase among the organic solvents examined. The optimal concentration of acetyltrimethylsilane, concentration of crude enzyme, volume ratio of the aqueous to the organic phase, temperature and the buffer pH value were 14 mM: , 61.4 U ml-1, 13% (v/v), 30 degrees C and 4, respectively. The substrate conversion and the product enantiomeric excess were 95% and 98% under the optimized conditions. Acetyltrimethylsilane was a better substrate of the enzyme than its carbon counterpart.

The present experiment was conducted to assess the efficacy of liquid methionine hydroxy analogue-free acid (MHA-FA) in comparison to DL-methionine (DL-Met) in broilers. 567 day-old Avian chicks were divided into 7 treatments with 5 replicates of 16 birds each. During the 35d (7-42 d) experimental periods chicks were given two basal diets. From 7 to 21d of age, a starting basal diet containing 19.5% protein and 0.33% methionine was supplemented with two graded levels of DL-Met (0.070 and 0.160%) or four levels of MHA-FA (0.118, 0.143, 0.221 and 0.268%). From 22 to 42d of age DL-Met (0.050 and 0.080%) or MHA-FA (0.071, 0.074, 0.112 and 0.140%) were added to a finishing basal diet with 18.0% protein and 0.28% methionine. Chicks fed on supplemental DL-Met or MHA-FA had significantly higher (p<0.05) body weight gain and feed conversion ratio (FCR) than the control group from 7-21d of age. During the finishing phase (22-42 d), body weight and weight gain of chicks in DL-Met or MHA-FA treatments were similar to those in the control, but FCR was improved (p<0.05) with supplementation of DL-Met or MHA-FA. Breast yield was higher (p<0.05) on DL-Met or MHA-FA supplemented than un-supplemented diets. The thigh meat yields emanating from diets with DL-Met or MHA-FA were lower (p<0.05) than that in control. Abdominal fat was also higher in broilers fed the control diet than in DL-Met or MHA-FA supplemented treatments. Methionine requirement of broilers was calculated to be 0.44 and 0.35% and cystine requirement was 0.35 and 0.31% for the starting (7-21 d) and finishing phase (22-42 d), respectively. The efficacy of MHA-FA in comparison to DL-Met for weight gain was 64 and 85% and for FCR was 55 and 60% at 7-21 and 22-42 d of age, respectively, while it was 74, 72, 52 and 48% for breast yield, thigh meat production, body energy content and energy deposition ratio at 42 d of age, respectively. In conclusion, in practical diet formulation for broiler chicks the average bioavailability of MHA-FA relative to DL-Met could be considered as 60 and 73% for 7 to 21d and 22 to 42 d of age, respectively.

Six barrows, average initial BW 20.2 + 0.9 kg, were fitted with a pancreatic pouch re-entrant cannula. Following a 14-d recuperation period, the pigs were fed two diets according to a crossover design, twice daily. Two maize starch-based diets were formulated to contain 12 and 24% CP from soyabean meal. The experiment consisted of 2 periods of 12 d each. The average BW at the start of periods 1 and 2 were 24.0+ 1.1 and 31.3 + 2.6 kg, respectively. The average BW at the conclusion of the experiment was 40.2 +1.6 kg. The daily volume of secretion was slightly higher (P < 0.05) in pigs fed the low compared with the high protein diet. There were no differences (P>0.05) in total protein output in pancreatic juice although the protein concentration (g/1" 1) was higher (P<0.05) in pigs fed the high protein diet. There was no effect (P>0.05) of dietary CP level of the total activities (units 24 h" 1) of chymotrypsin, trypsin, amylase and lipase. The specific activities (units f') of chymotrypsin and amylase were higher (P < 0.05) when the high protein diet was fed. An increase in BW augmented (P<0.05) the secretion of volume of pancreatic juice, protein output and total activities of chymotrypsin and lipase. In conclusion, there were no differences in total protein output and total enzyme activities in pancreatic juice when the dietary CP content ranges from 12 to 24%.