Commercial broilers have a short production cycle and a high requirement for energy (3000 kcal/kg in starter phase and 3200 kcal/kg in finisher phase). Therefore, the need to add energy rich lipids to their diet is inevitable. Digestibility of fat depends on its multiple properties: chain length, the composition of fatty acids, ratio of saturated/unsaturated fatty acids and free fatty acids. The high cost of vegetable oils and less availability due to their consumption in human diet are the main reasons for searching for cheaper alternative fat sources. Animal oils like poultry and fish oil are the by-product of rendering plants and after refining, they are used in poultry diets as an energy source. Due to presence of impurities and free fatty acids, the digestibility of animal fat is lower. There is a limited amount of bile acids and lipase available during early age and when birds are reared on high energy diet (finisher phase). Supplementation of emulsifier or lipase in broilers’ diet increase fat utilisation. Emulsifiers increase fat digestibility by increasing active surface area of lipid droplets. Lysolecithin and lysophospholipids are produced from hydrolyses of lecithin and phospholipids by phopholipase A2. The bile acids are mainly composed of cholic acid, hyodeoxycholic acid and chenodeoxycholic acid and have strong emulsification properties. Triacylglyceryl acylase (lipase) is an enzyme involved in catalysis and the hydrolysis of lipids. It can be concluded that use of emulsifier and lipase in broiler diet improves growth performance, nutrient digestibility and intestinal histology in broilers.

Context: Selenium is an important trace mineral and plays an important role in protection against oxidative stress and improving productivity of poultry. Aim: This study aimed to evaluate the effects of different maternal selenium sources on growth performance, antioxidant status, immune responses, and meat quality of broiler offspring. Methods: In total, 600 female and 180 male 50-week-old Ross-308 broiler breeder birds were randomly allocated to four treatments with five replicates, each having 30 females and nine males. The birds were given 2-week adaptation followed by 7-weeks of feeding of one of four experimental diets. In one dietary treatment, birds were fed a basal corn–soybean-based diet supplemented with inorganic selenium (sodium selenite, SS), while in the other three dietary treatments, birds were given either of the following organic selenium sources: selenium enriched yeast (SY), hydroxy-selenomethionine (OH-Se-Met) or l-selenomethionine (l-Se-Met), each included at the rate of 0.3 mg/kg in their experimental diets. During the 7th week of experiment, 350 eggs were collected from each dietary treatment. After incubation, 250 healthy chicks per parental dietary treatment were divided into five replicates with 50 birds each. Offspring from all parental dietary treatments were fed the same basal diet supplemented with 0.15 mg/kg of selenium from inorganic source during the starter (1–21 days) and finisher (22–35 days) phases. Key results: Maternal selenium sources had no effect on feed intake, weight gain, feed conversion ratio, nutrient efficiency, carcass parameters, and antibody titre against Newcastle disease virus in broiler offspring. Drip loss and oxidative stability of breast meat, plasma total antioxidant and glutathione peroxidase status were improved in the offspring at Day 21, by inclusion of organic selenium in parent broiler breeders’ diet; however, these parameters were not affected at Day 35. Conclusions: Maternal dietary organic selenium improved antioxidant status and meat quality in broiler offspring at the end of starter phase; however, dietary maternal selenium sources had no effect on productivity, immune responses, and carcass traits in broiler offspring. Implications: This may provide consideration for more effective sources of selenium for improving meat quality of poultry birds especially in early stage of grow-out period.