In addition to being an essential amino acid in protein synthesis, threonine is an integral component of gut function. To verify the effects of l-threonine on gut function, Babcock Brown layers (n = 960; 40 wk of age) were allocated to 5 dietary treatment groups, each of which included 6 replicates of 32 hens. Each group received the same basal diet formulated with corn, peanut meal, and crystalline amino acids. l-Threonine was added to the basal diet at 0 (control), 0.1, 0.2, 0.3, and 0.4% for 8 wk to achieve 0.47 (NRC), 0.57, 0.67, 0.77, and 0.87% threonine, respectively. Expressions of jejunal and ileal mucin 2 mRNA were increased linearly by increasing l-threonine (P < 0.01). At 0.4% l-threonine, the concentrations of IgA antibody in the mucosa of the ileum increased linearly (P < 0.01). No differences attributable to treatment were found among groups in the activity of digestive enzymes in the jejunum or ileum. It was concluded that dietary threonine requirements as reported in current NRC recommendations are insufficient for modern commercial laying hens raised in summer climates. The results suggest that threonine might function as a nutrient immunomodulator in maintaining intestinal barrier function.

SUMMARY. Babcock Brown layers (n = 960), 40 wk of age, were allocated to 1 of 5 dietary treatments groups, each of which included 6 replicates of 32 hens. Each

Ross 308 broiler chicks (n = 240) aged 1 day were assigned to five groups for eight replicates (six chicks for each) (3♂ and 3♀). Basal dietary groups were supplemented by 2000, 4000, and 6000 mg/kg cinnamon (CN) for 21 days. Basal diet alone was used as a negative control, and basal antibiotic diet (Colimox) was used as a positive control. At 10, 14, and 21 days of age, chicks that received 2000 mg CN and Colimox had a higher body weight, resulting in an increase in body weight gain. CN also resulted in the maximum improvement in the feed conversion ratio and feed efficiency over 1–21 days at the level of 2000 mg/kg. At days 10, the maximum relative breast weight was 2000 mg/kg of CN. Mean serum albumin concentrations, duodenal villus height, and goblet cell density increased (p < 0.05) by 2000 mg/kg of CN, and mean serum globulin and total protein concentrations and crypt depth increased (p < 0.05) by 6000 mg/kg of CN compared with control. Increased cecal Escherichia coli number was CN dose-dependent. In conclusion, dietary inclusion of 2000 mg/kg CN can be applied as an alternative to in-feed antibiotics for broiler starter diet.

A total of 192 one-day-old Ross 308 broiler chicks were assigned to 4 treatments with 8 replicate cages of 6 chicks (3♀ and 3♂) per cage according to a completely randomized block design. The dietary treatments were a basal diet (control) and a control diet supplemented with 1,000, 3,000, and 5,000 mg/kg Rumex nervosus leaves meal (RN). Gallic acid and some volatile compounds were detected in the RN extract. On day 10 of age, BW was improved (P = 0.016) with supplemental RN (1,000–5,000 mg/kg). On day 14 of age, dietary application of RN up to 3,000 mg/kg increased BWG (P = 0.003) compared with control, while a 1,000 mg/kg RN had the best feed conversion ratio (P = 0.016). On day 10 of age, samples were taken on a single female bird per replicate. The addition of RN (1,000–5,000 mg/kg) increased (P < 0.001) serum albumin and triiodothyronine levels and maximized the relative weight of breast meat (P = 0.003). Feeding a diet with 1,000 mg/kg RN resulted in greater duodenal villus height (P < 0.001) than control and the diet with 5,000 mg/kg RN. Broilers fed diet supplemented with 1,000 mg/kg RN had the best duodenal villus surface area (P < 0.001). Feeding a diet with 1,000 mg/kg RN decreased (P < 0.001) cecal Escherichia coli count compared with control and the diet with 5,000 mg/kg RN. Salmonella spp. count tended to increase with 5,000 mg/kg RN leaves meal (P = 0.069, linear P = 0.026). In conclusion, R. nervosus leaves meal could be considered as a phytogenic feed additive in broiler diets up to a 1,000-mg/kg inclusion rate because of its combined positive effects on BWG, feed conversion ratio, villus height, villus surface area, serum albumin and triiodothyronine hormone, and cecal E. coli during the starter period (day 10–14 of age). Further study is required to elucidate its molecular mechanism.

Chia (Salvia hispanica L.) is a member of Labiate family and its seeds are rich in phenolic compounds and polyunsaturated fatty acids (PUFAs) which could enhance the performance and productivity of birds. This study was carried out to determine the effects of supplementation with cold-pressed chia oil at different concentrations on the growth performance, carcase traits, haematology, blood chemistry, immunity and antioxidant status of growing quails. A total of 240 growing quails (1 week-old) were divided equally into five groups (4 replicates with 12 birds each). The experimental groups were G₁ (basal diet), G₂ (basal diet + 0.4 g chia oil/kg diet), G₃ (basal diet + 0.8 g chia oil/kg diet), G₄ (basal diet + 1.2 g chia oil/kg diet) and G₅ (basal diet + 1.6 g chia oil/kg diet). Birds in the G₂ group exhibited the highest body weight at 3 and 5 weeks of age, and the highest body weight gain at 1–3 weeks (6.24 g) and 1–5 weeks (6.17 g). Birds fed diets enriched with 0.4% chia oil exhibited the best FCR values. Dietary supplementation with chia oil increased the red blood cells (RBCs), white blood cells (WBCs), haemoglobin (HGB) and haematocrit (HCT) when compared to the control group (G₁). The antioxidant and immunity parameters were not affected by the supplementation of diet with chia oil. This study showed that quail diet supplementation with 0.4 g chia oil/kg diet improved the growth performance, certain blood parameters and lipid profile.

The gastrointestinal tract plays an important role in studies of avian ontogenies because of its key function in nutrient intake. The pattern of inte