An experiment was conducted to evaluate the effects of dietary glutamine (Gln) and arginine (Arg) supplementation on performance, intestinal morphology and ascites mortality in broilers. A total of 675 day old chicks were randomly allocated to 9 experimental groups in a 3×3 factorial arrangement based on a completely randomized design with 5 replicates of 15 chicks. Three levels of dietary Gln (0%, 0.5%, and 1%) and Arg (100%, 130%, and 160% of Ross recommendation) supplementation were used in ascites inducing condition (15°C ±1°C) from 7 to 42 days of age. Dietary supplementation of Gln increased body weight gain during grower, finisher and total periods (p<0.05) and increased feed intake during total period. Ascites mortality was decreased by Gln supplementation (p<0.05). Gln supplementation increased the villus height (VH) and crypt depth (CD) in duodenum and jejunum (p<0.05). Arg supplementation decreased CD in duodenum and jejunum, and increased ileum villus width (VW) and also VH/CD ratio in duodenum and jejunum (p<0.05). Both Gln and Arg increased the goblet cell number (GCN) in duodenum whereas Gln supplementation decreased GCN in jejunum and ileum (p<0.05). The Gln×Arg interaction were observed for right ventricle (RV)/total ventricular (TV) ratio, VH, VW, CD, VH/CD. It was concluded that dietary 0.5% Gln alone or along with 130% Arg of Ross requirement, improve the intestinal morphology and performance and hence decrease the ascites mortality in broiler chickens with cold induced ascites.

1. The aim of the present study was to determine the effects of early-age cold conditioning (CC) on performance, ascites mortality, thyroid hormones status and immune response (leucocytes count) of broiler chickens. 2. A total of 336 chicks at 2 and 3 d of age were exposed to 20 or 25°C (for 3 or 6 h) in a 2 × 2 × 2 factorial experiment, while a control group was kept under normal temperature conditions (30°C). Thereafter, both control and cold conditioned birds were reared under standard conditions until 42 d of age. 3. The results showed that performance (weight gain and feed efficiency) was improved by CC at the end of the rearing period. Carcase traits (breast, thigh and abdominal fat percentage) were not affected by different treatments. Heart weight was lower in cold conditioned birds accompanied with lower ascites mortality. Total leucocyte count was higher in CC birds. Higher concentrations of thyroxin (T₄) were found in plasma of treated groups, while triiodothyronine (T₃) to T₄ ratio was decreased. 4. In conclusion, it seems that early age CC improves performance and reduces ascites mortality of broilers through altered thyroid hormones metabolism and leucocyte function. According to the results, the best timing for CC of broilers was 20°C for 6 h at the age of 2 d, and no significant benefit was observed by repeated CC.

Improving reproductive performance is one of the most important factors affecting the profitability of dairy herds. This study investigated the effect of feeding a high starch (HS) diet and body condition score (BCS) at calving on blood metabolites, fertility and ovarian function and milk production in Holstein dairy cows. One hundred seventy-four multiparous cows were fed common close-up and early lactation diets during the first 15 days in milk (DIM). Cows were randomly assigned to 1 of 2 experimental diets from 16 until 50 DIM (n = 87 per group); normal starch (228 g/kg diet DM; NS) or HS (270 g/kg diet DM; HS) diets. Each treatment group was further subdivided based on BCS at calving as normal BCS (BCS ⩽ 3.5; normal BCS (NBCS); n = 45) or high BCS (HBCS) (BCS ⩾ 3.75; HBCS; n = 42). A significant difference was detected for increased milk production (47.24 v. 44.55 kg/day) and decreased milk fat (33.93 v. 36.33 g/kg) in cows fed HS or NS, respectively. Plasma glucose and insulin concentrations were significantly higher in cows fed the HS compared to the NS diet. Diets significantly affected DIM at first artificial insemination (AI, 79.51 ± 3.83 v. 90.40 ± 3.83 days for cows fed HS and NS diets, respectively). High BCS groups had greater milk fat content and elevated plasma nonesterified fatty acids (NEFA), β hydroxybutyrate (BHB) and bilirubin concentrations. In general, feeding higher starch diets to normal BCS cows during the first 50 DIM improved productive and reproductive performance of early-lactating dairy cows.

Two separate studies were conducted in growing broiler chickens to examine the relative bioavailability (RBA) of L-smethionine (L-Met) vs. DL-methionine (DL-Met) in the starter (0-10 d, Experiment 1) and grower (11-24 d, Experiment 2) periods. In each experiment, 540 male Arian broilers were weighed and randomly allocated to nine dietary treatments in a completely randomized design with 6 replicates: basal diet (BD) with no methionine (Met) supplementation and eight diets supplemented with incremental levels (0.8, 1.6, 2.4, and 3.2 g/kg) of DL-methionine (DL-Met) or L-methionine (L-Met). Supplementation of the BD with either DL-Met or L-Met improved growth performance (P < 0.05), breast percentage (P < 0.05), and antioxidant status (P < 0.05) of broilers in both experiments. Orthogonal contrasts showed that L-Met supplementation compared to DL-Met (specifically at levels 0.8 and 1.6 g/kg) improved average daily gain (ADG, P < 0.05), average daily feed intake (ADFI, P < 0.01), and feed to gain ratio (F:G, P < 0.01) in the starter phase. In the grower phase, L-Met supplementation (specifically at levels 0.8 and 1.6 g/kg) only improved F:G (P < 0.05) compared to DL-Met, with no significant differences in the other performance parameters. Nonlinear regression analysis showed that RBA of L-Met based on carcass percentage was significantly (P < 0.05) higher than that of DL-Met in the starter phase. Based on the findings of this study, it seems that using L-Met compared to DL-Met may improve the feed efficiency and carcass percentage of young growing broiler chickens.