In this study, we investigated the effect of methionine isomers (D-and L-methionine) on growth performance, blood metabolite levels, nutrient digestibility, intestinal morphology, and foot pad dermatitis in broilers challenged with acute heat stress. In total, 240 broilers were randomly allocated in a 2×2 factorial arrangement consisting of two dietary treatments (D-vs. L-methionine) and two thermal environmental conditions (thermo-neutral vs. acute heat stress). Methionine isomers were added to the diet as an ingredient according to the diet formulation. The broilers were exposed to acute heat stress at 33℃ for 5 h on day 14. The average daily gain and feed conversion ratio of birds fed L-methionine were higher than those fed D-methionine (P＜0.05) from the time of hatching till 21 days. Induced acute heat stress impaired (P＜0.05) the daily gain and feed intake of the broilers on day 21. Furthermore, the blood urea nitrogen levels of birds subjected to acute heat stress on days 14 and 21 were higher (P＜0.05) than those of their counterparts. Longer villi (P＜0.05) were observed in broilers fed L-methionine-supplemented diet than in those fed D-methionine-supplemented diet on day 14, irrespective of thermal environmental conditions. Heat stress reduced (P ＜0.01) nutrient digestibility of the broilers on days 14 and 21. Higher incidence and severity of foot pad dermatitis were observed (P＜0.05) in broilers fed diet containing D-methionine than in those fed L-methionine-supplemented diet. In conclusion, L-methionine-supplemented diet improved growth performance, overcame growth depression, and reduced the incidence of foot pad dermatitis when broilers were exposed to acute heat stress in the starter period.

This study investigated bioaccumulation and toxicity derived from heavy metals in laying hens. The 160 52week old laying hens were divided into 5 treatments with 8 replicates of 4 birds per pen. The treatments consisted of the control diet (without heavy metals), control diet with half the available dosage (AD, 5 ppm lead and 0.2 ppm mercury), AD (10 ppm lead and 0.4 ppm mercury), 2-fold AD (20 ppm lead and 0.8 ppm mercury), and 3-fold AD (30 ppm lead and 1.2 ppm mercury), and were provided to the laying hens for 8 weeks. Food and water were provided on an ad libitum basis at all times. Body weight and food intake were recorded once every two weeks, and eggs were collected and recorded daily. Two birds from each pen were euthanized to collect blood and organ samples on week 4 and 8. The 3-fold AD diet reduced food intake compared to that of the control and AD diets (P＜0.05). Hens fed the half AD diet had darker yolk compared to those fed the control and AD diet on week 4 (P＜0.05). Hens fed the 2-and 3-fold AD diets had increased relative liver weight, blood glutamic pyruvic transaminase and glutamic oxaloacetic transaminase levels (P＜0.05), while F1 follicle weights decreased on week 4 and 8. No difference was found in egg production rate, egg quality, ovarian follicle, blood metabolites including protein, globulin, albumin, and urea nitrogen throughout the study (P＞0.05). Heavy metal concentrations in the liver, eggs, and feathers were not detected at both week 4 and 8. Our results indicate that in-feed heavy metals for layer diets up to 30 ppm of lead and 1.2 ppm of mercury brought on hepatic dysfunction increasing blood metabolites that are associated with liver inflammation.

We aimed to compare the combinatorial effect of 3,4,5-trihydroxybenzoic acid (THB) and oregano extracts (OE) with THB alone on the growth performance and elimination of deleterious effects in coccidiosis-infected broilers. A total of 210 one-day-old broilers were randomly assigned to one of five dietary treatments, with six replicates each, for 35 days. Dietary treatments were: 1) non-challenged, non-treated (NC); 2) challenged, non-treated (PC); 3) PC+ Salinomycin (0.05 g/kg; AB); 4) PC+THB (0.1 g/kg; THB); and 5) PC+THB+OE (0.1 g/kg; COM). On day 14, all groups except for NC were challenged with a 10-fold dose of Livacox ® T anticoccidial vaccine to induce mild coccidiosis. All treatments significantly improved ( P <0.05) body weight, average daily gain, and average daily feed intake, compared to PC, on days 21, 28, and 35. However, all treatments significantly reduced ( P <0.05) the feed conversion ratio of PC by more than 14.60% on day 35, 11.76% during growing period, and 10.36% through the entire period. Broilers receiving anticoccidial treatments had 54.23% and 51.86% lower lesion scores ( P <0.05) at 4 and 7 days post-infection, respectively, compared to PC. Additionally, the villus height of COM was significantly longer ( P < 0.05) than that of THB. Although the molecular action of COM remains unclear, OE addition to THB reduced the shedding of oocysts better than THB alone ( P <0.05, 9-11 days post-infection). Most importantly, COM effectively minimized the mortality of challenged birds from as high as 11.90% (PC) to 0%, a level similar to NC and AB, while THB maintained a mortality of 2.38%. In conclusion, the anticoccidial effect of THB can be enhanced by the addition of OE for better animal performance and the elimination of deleterious effects from coccidiosis-infected broilers for 35 days.

The original version of this Article contained an error in the spelling of the Hyun-Jung Jung, which was incorrectly given Jung-Hyun Jung.