ABSTRACT This study was conducted to investigate the effects of Arthrospira platensis (Spirulina platensis, SP) on feed intake, feed conversion ratio, egg weight, hen day egg production, intestinal microflora, heat stress biomarkers, and HSP70 gene expression in laying Japanese quails (Coturnix coturnix japonica) suffering heat stress condition. A total of 250 female quails were allocated to 5 treatments, 5 replicates and 10 birds in each replicate in a completely randomized design. Experimental treatments included: 1) basal diet, 2) basal diet+ 0.03 % probiotic, 3) basal diet+ 0.1 % SP, 4) basal diet+ 0.3 % SP, 5) basal diet+ 0.5 % SP. During the last 6 days of the experiment, the quails were exposed to 8h of 34±1°C. The birds had free access to feed and water during the experiment. The results showed that using probiotic and different levels of Spirulina had no significant effect on laying performance of Japanese quails (p>0.05). Probiotic supplement increased Lactobacil bacteria population in laying quails’ ileum under heat stress (p<0.05). Different levels of SP decreased Escherichia coli population in laying quails’ ileum suffering heat stress (p<0.05).SP at the level of 0.5% caused the lowest blood Malondialdehyde level, heterophil, and H/L ratio (p<0.05).However, HSP70 gene expression in the heart or the liver of laying quails was not different (p>0.05). In conclusion, the results of the present study revealed that SP at the level of 0.5 % has the potential to be considered as a probiotic alternative in the diet of laying quails suffering heat stress condition.

In order to estimate the crude protein (CP) equivalence value of Natuzyme-p (NP) enzyme by using regression response equations, two experiments were carried out using Ross (308) broiler chicks. Graded levels of dietary CP (while amino acids levels were kept constant) and NP enzyme were used to derive the regression equation in the first experiment. Four levels of dietary CP and NP enzyme were fed to 160 feather-sexed male broiler chicks during the starter (0-28 d of age) and grower (28-42 d of age) period. Each diet was offered to four replicates of five chicks in a completely randomized design. Results obtained in experiment one failed to fit a regression equation between BW, dietary CP levels and NP enzyme. In experiment two, graded levels of CP changed along with the levels of lysine (Lys), Met+Cys and threonine (Thr). Regression equations between BW and dietary CP and NP enzyme were derived. Nonlinear and linear equations were generated for enzyme and CP. Based on an assessment of r² and P value, nonlinear equations were used to determine enzyme equivalence. The derived regression equations of body weight for CP were set to be equal with those obtained for NP and were solved; enzyme equivalence value for CP was calculated by subtracting the obtained value from CP content of basal diet. Crude protein equivalence value of NP at 28 and 42 d of age was estimated to be 0.96 and 0.38 %, respectively.

To clarify the effects of high (20 and 40% more than normal) and low (20% less than normal) daily feed allowance on egg and body parameters, ovarian morphology and plasma glucose, cholesterol, triacylglycerol, leptin-like hormone, nitrite/nitrate and gene expression of inducible nitric oxide synthase (iNOS) in the granulosa layer of F1 follicle, broiler breeder hens (30-week-old) were fed for 30 days. Egg and body parameters significantly changed between treatments (p<0.05). Effect of different level of feed intake on ovarian morphology parameters was significant (p<0.05), except for white follicles. After 30 days of experiment, plasma nitrite/nitrate (as a index of plasma nitric oxide) and leptin-like hormone increased in FI+20% and FI+40% groups as compared to controls (p<0.05). Plasma level of leptin-like hormone also significantly (p<0.05) increased in FI+40% group. The relative amount of iNOS mRNA expression in the granulosa layer of F1 follicles was significantly higher in FI-20% and FI+40% groups than in control group only after 4 weeks of experiment. The amount of these elevations in the FI-20% and FI+40% groups were 32.4% and 60.9% respectively. It was concluded that iNOS gene is normally expressed in follicular granulosa cells of F1 follicle of broiler breeder hens 2-4 hours before ovulation. However, over- and underfeeding of hens increased iNOS expression in F1 follicle, which may be one of the atresia-inducing factors in hierarchical follicles as shown by the significant (p<0.05) increase of shrunken follicles in the ovary of over- and under-fed broiler breeder hens after 30 days of feeding.