This study aimed to assess the effects of different arginine (Arg) to lysine (Lys) ratios on feed intake, nutrient digestibility, growth performance, carcass characteristics, and antibody titers of Newcastle disease (ND) and infectious bronchitis (IB) disease in broilers during 35 days of trial. For this purpose, a total of 816 day-old broiler birds having an average weight of 38 ± 3 g were divided into six dietary treatments in such a way that each treatment had eight replicates and each replicate had 17 birds. The treatments were 0.95 (1.19/1.25, 1.12/1.18, and 1.05/1.1), 1 (1.25/1.25, 1.18/1.18, and 1.1/1.1), 1.05 (1.31/1.25, 1.24/1.18, and 1.17/1.1), 1.10 (1.38/1.25, 1.30/1.18, and 1.23/1.1), 1.15 (1.44/1.25, 1.36/1.18, and 1.28/1.1), and 1.20 (1.50/1.25, 1.42/1.18, and 1.34/1.1) Arg/Lys divided into different amounts according to the nutritional needs of starter, grower, and finisher diets, respectively. The results showed that in the finisher phase, the FI was influenced cubically, while in the overall period, a quadratic effect was observed for the FI (p < 0.05). The results of BWG showed that BWG was linearly increased in birds given different Arg/Lys in the grower, finisher, and overall period (p < 0.05). The results also showed that during the grower, finisher, and overall phases, the body weight gain (BWG) was better in birds fed with 1.05 and 1.10 Arg/Lys (p < 0.05). Furthermore, a better feed conversion ratio (FCR) was shown in the starter and grower phases at 1.10 and 1.15 Arg/Lys (p < 0.05). The results of nutrient digestibility explored showed that the experimental treatments had a better effect (p < 0.05) on dry matter and crude fat digestibility in birds fed with 1.19/1.25, 1.12/1.18, and 1.05/1.1 and 1.25/1.25, 1.18/1.18, and 1.1/1.1 Arg/Lys in their diets while the crude protein digestibility remained unaffected with different treatments (p > 0.05). The treatments had no effect (p > 0.05) on relative organ weights, immune organs, and carcass characteristics. However, higher titers of ND and IBD were observed in birds fed with Arg/Lys of 1.38/1.25, 1.30/1.18, and 1.23/1.1 and 1.50/1.25, 1.42/1.18, and 1.34/1.1 in their diets (p < 0.05). Based on the results of the current study, it is concluded that the inclusion levels of 1.38/1.25, 1.30/1.18, and 1.23/1.1, and 1.44/1.25, 1.36/1.18, and 1.28/1.1 Arg/Lys resulted in better growth performance and immune response in the broiler birds, respectively. Therefore, adjusting the levels of Arg/Lys in feed is recommended to enhance broilers’ growth performance and immune response.

This study evaluated the effect of biochars on growth performance, nutrient digestibility, carcass yield, bone mineralization, litter quality and footpad lesions in broilers. Eight hundred day-old chicks were randomly divided into four treatments, 10 replicates per treatment (20 birds/replicate) for 35 days. Treatments were basal diet (control), a control diet with corncob (CC) biochar (1%), a control diet with wheat straw (WS) biochar (1%) and a control diet with sugarcane bagasse (SCB) biochar (1%). Body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR) were recorded weekly. Nutrient digestibility, bone mineralization and carcass parameters were determined on the 21st and 35th days, while footpad lesions and litter quality were also assessed. The results revealed significant improvement (p < 0.05) in FI, BWG and FCR with supplementation. Nutrient digestibility was higher (p < 0.05) in the SCB biochar group. Tibia calcium and phosphorus levels were enhanced (p < 0.05) in the WS and SCB biochar groups, respectively. Footpad lesions were significantly lower (p < 0.05) in the CC biochar group, while litter quality was improved (p < 0.05) in the WS biochar group. Lymphoid organ relative weight results revealed that spleen weight was not affected by biochar supplementation in diet (p > 0.05), while dietary supplementation of CS and WS biochar in the diet resulted in the highest relative weights of thymus and bursa (p < 0.05). However, dietary supplementation of WS, SC and SCB biochar supplementation had affected positively the log value of the ND virus and IBV titers in birds. Overall, dietary supplementation of 1% biochars enhances growth performance, bone mineralization, footpad health immunity and litter quality in broilers.

The objective of this experiment was to check the effect of supplementation with exogenous bile acid (BA), emulsifier (Em) and their blend on performance parameters, fat utilization, relative organ weights, and blood lipid profile in growing broilers. A total of 800 day-old broiler chicks were procured from a local hatchery and distributed into four experimental treatments in completely randomized design, with ten replicates with twenty birds each. The treatments were: Control (CON) (basal diet without any Em or BA), CON supplemented with 0.03% Em, CON supplemented with 0.025% BA and CON supplemented with a blend of Em (0.03%) and BA (0.025%). Starter (0-7), grower (8-21) and finisher (22-35) diets were offered to birds for 35 days. Body weight gain, feed intake and feed conversion ratio were recorded weekly. On days 21 and 35, nutrient digestibility was assessed using the acid-insoluble ash method. Blood lipid profiles and internal organ weights were measured at the end of the trial. The results of digestibility assays carried out on days 21 and 35 showed that supplementing BA alone, Em alone or their combination increases (p<0.05) body weight gain and improves (p<0.05) feed conversion ratio on days 7 to 21, days 21 to 35, and days 0 to 35. Results also showed that supplementation of BA, Em and their blend in the diet improve dry matter and fat digestibility (p<0.05), while the level of low-density lipoprotein decreased (p0.05); however, BA, Em and their blend increased the weight of the spleen (p<0.05). In conclusion, BA, Em and their combination enhance growth performance and nutrient digestibility in broilers without negatively affecting lipid metabolism.

In the current study, Nigella sativa (NS) seed powder was evaluated as a potential natural alternative to antibiotic growth promoters in the diet of broilers to check its impact on the growth performance, antioxidant status, carcass characteristics, and meat quality of broilers. For this purpose, a total of 400 one-day-old male broiler chicks (Ross-308; Gallus gallus domesticus) were divided into five dietary treatments: negative control, 50 mg lincomycin/kg feed, 1% NS, 2% NS, and 3% NS (NS added on top of the basal diet at 10, 20, and 30 g/kg). Each treatment had 10 replicates and each replicate had 8 birds, and the total duration of the experiment was 35 days. Results showed that broilers fed 1% NS exhibited the highest overall body weight gain (p < 0.001), and NS supplementation improved the feed conversion ratio (FCR) during the finisher phase and in the overall phase (0–35 d) (p < 0.001), with the best overall FCR at 1% NS, whereas mortality did not differ among treatments (p > 0.05). Total tract nutrient digestibility and ileal crude protein and dry matter digestibility were improved by 1% and 2% NS supplementation (p < 0.05). NS supplementation reduced thiobarbituric acid (TBA) values and increased glutathione peroxidase activity in both thigh and breast meat, and increased superoxide dismutase activity in breast meat at all NS levels and in thigh meat at 2% and 3% NS (p < 0.05). Dressing percentage, breast and thigh meat yield, and relative organ weights did not differ among treatments (p > 0.05). NS increased water-holding capacity and reduced shear force (at 2% and 3% NS) and drip loss (at 3% NS) (p < 0.05), whereas meat pH at 1% and 2% NS was lower than in the AGP group but did not differ from the control. In conclusion, dietary inclusion of NS, particularly at 1–2%, enhanced body weight gain, feed conversion ratio, nutrient digestibility, antioxidant status, and meat quality of broiler chickens, although carcass yield was not significantly affected.