The effect of probiotic, prebiotic and synbiotic inclusion in diet on performance, serum lipids, and intestinal microflora of Japanese quails

Japanese quail is considered as a beneficial bird because of its characteristics such as rapid growth, early maturity, high egg production, breeding times and short incubation period (Lotfipour and Shakeri, 2011). Additives such as probiotics and prebiotics are used as alternatives to antibiotic growth promoters today (Zare Shahneh et al. 2007). Primalac is a kind of commercial probiotics that contains Lactobacillus casei, Lactobacillus acidophilus, Bifidobacterium thermophilum, and Enterococcus faecium (Salehimanesh et al. 2016). Its characteristics include increasing the population of the gastrointestinal tract microbes, increasing livestock production, reducing drug use, reducing mortality and reducing diarrhea in the flock (Midilli et al. 2008). Fermacto (kind of commercial prebiotics) is the product of elemental fermentation of Aspergillus oryzae. Fermacto have effects of increasing the flock's uniformity, reducing the passage of foodstuffs, eliminating the competitive challenge, developing intestinal villi, increasing energy and protein absorption, increasing the absorption and storage of minerals especially calcium and phosphorus, enhancing the immune system, and improving weight gain on time of stress (Ghahri et al. 2013). An experiment was conducted as a completely randomized design using 400 day-old quail chicks (mixed sex) with four treatments, five replicates, and 20 quail chicks in each replicate from 1 to 42 days of age. Experimental treatments were included: (1) control group (basal diet without any feed additive), (2) basal diet contains 0.9 g/kg Primalac, (3) basal diet contains 2 g/kg Fermacto and (4) basal diet contains 0.9 g/kg Primalac + 2 g/kg Fermacto. Diets were formulated to meet or exceed the nutritional requirements of Japanese quail as indicated in the standard tables (NRC, 1994). Quails in each replicate were weighed weekly and feed intake was determined at the end of each week. From these data, average daily weight gain, average daily feed intake and feed conversion ratio were calculated. On day 42 of experiment, two birds (one male and one female) from each replicate were selected, then weighed, were slaughtered and carcass yield and carcass components including breast, thighs, wings, abdominal fat, fat around neck, and bursa of Fabricius were weighed using a digital scale and their relative weight to body weight were calculated. The length of the various parts of the small intestine, including the duodenum, jejunum and ileum, was measured after the separation from the mesenteric with the ruler. To study the blood metabolites, blood samples were taken from the wing vein of two quails in each replicate (one male and one female) on day 42 and then, sera were separated to measure triglycerides, cholesterol, HDL, and LDL using enzymatic kits via colorimetric method. To determine ileal microbial population of quails, after opening the abdominal cavity, ileum region, between Meckel’s diverticulum and ileocecal junction, separated by a sterilized scissor, about two centimeters of the ileum were transferred into sterile microtubes and were stored at -20 ̊C until studying E.coli, lactobacillus and coliform microbial populations (Roostaei-Ali Mehr et al. 2014). Eosin methylene blue agar medium (Merck, Germany) was used to culture E.coli. MacConkey agar (Merck,
Germany) and MRS (Merck, Germany) were used to cultivate coliforms and Lactobacillus, respectively. The results indicated that 0.9 g/kg probiotic Primalac, 2 g/kg prebiotic Fermacto, and 0.9 g/kg probiotic Primalac + 2 g/kg prebiotic Fermacto in diet had no significant effect on daily feed intake, daily weight gain, and feed conversion ratio (P>0.05). It was reported that the use of probiotic (Primalac) to the diet of Japanese quail had no effect on daily weight gain and daily feed intake (Rezaeipour et al. 2015). Several factors can affect the consumption of bird feed, including the physiological and nutritional factors, health and the rate of production and type of bird (Blair, 2008). The results indicated that treatments did not affected on weight of carcass and internal organs (P>0.05; Table 3). It was reported that using probiotic to the diet of Japanese quail had no effect on weight of carcass and carcass traits (Sahin et al. 2011). It was reported that addition of probiotic (Primalac) and prebiotic (Fermacto) to the diet of broilers did not have any effect on growth performance and carcass quality, carcass weight, carcass traits, breast, heart, abdominal fat, spleen, and bursa of Fabricius (Shirmohammad et al. 2015). Treatments had no significant effect on relative length of the small intestine segments (duodenum, jejunum and ileum) (P>0.05). Shirmohammad et al. (2015) reported that intestinal traits of broilers were not affected by Primalac and Fermacto. Since the most important feature of probiotics is their ability to settle in the gastrointestinal tract, native microbial strains of gastrointestinal tract are usually prepared as probiotics, so probiotics produced for broilers may not be suitable for establishment or proliferation in the Japanese quail digestive system. Treatments had no significant effect on triglyceride, cholesterol, HDL, and LDL (P>0.05). It is reported that the supplementation of the Japanese quail diet with Primalac did not have any effect on serum triglycerides, cholesterol, LDL, and HDL of broilers (Rezaeipour et al. 2015). Sahin et al. (2008) reported that cholesterol, triglyceride and glucose levels were not affected by experimental treatments when using synbiotic (Saccharomyces cerevisiae + mannan oligosaccharide) in Japanese quail diets. The levels of serum cholesterol and triglycerides in birds affected by diet and other factors such as age, sex, and environmental conditions (Haddadin et al. 1996). Non-significant changes for intestinal microflora were observed (P>0.05; Table 6). Researchers reported that the consumption of probiotic (Protexin) in the diet of quail did not have any significant effect on bacterial populations (Nasehi et al. 2015). When using feed additives, consideration of points such as rate of consumption, temperature, humidity, water consumption and environmental health are necessary (Chiang and Hsieh, 1995). It could be concluded that 0.9 g/kg probiotic (Primalac), 2 g/kg prebiotic (Fermecto) and synbiotic (0.9 g/kg probiotic Primalac + 2 g/kg prebiotic Fermecto) had not any positive effect on growth performance, carcass traits, length of small intestine, serum lipids as well as the number of Lactobacillus bacteria, coliforms, and E.coli in Japanese quail.