The effects of stocking density on the performance, egg quality, leukocyte concentration, blood biochemistry, corticosterone levels, bone mineral density, and noxious gas emission of laying hens were investigated. Eight hundred 34-week-old Hy-Line Brown laying hens (Gallus gallus domesticus) were randomly assigned to one of 4 treatments, each of which was replicated 4 times. Four stocking densities, including 5, 6, 7, and 10 birds/m2, were compared. A commercial-type basal diet was formulated to meet or exceed nutrient recommendations for laying hens from the National Research Council. The diet was fed to the hens ad libitum for 8 wk. Results indicated that hen-day egg production, egg mass, and feed intake were less for (P < 0.01) 10 birds/m2 stock density than other stock densities. Production rate of floor and broken eggs and eggshell strength were greater (P < 0.01) for 10 birds/m2 stock density than other stock densities. There were no significant differences in the level of leukocytes among densities. However, heterophils and the H/L ratio were greater (P < 0.01) for 10 birds/m2 than in stock density of 6 or 7 birds/m2. Serum corticosterone was greater (P < 0.01) 10 birds/m2 than stock density than other stock densities. Litter moisture and gas emission (CO2 and NH3) were greater (P < 0.01) for 10 birds/m2 than stock density than 6 and 7 birds/m2 stock density. Bone mineral content was not influenced by increasing stock density. However, bone mineral density was less (P < 0.05) for 10 m2 stock density than other stock densities. These results indicate that increasing the density beyond 5 birds/m2 elicits some negative effects on laying performance of Hy-Line brown laying hens.

This study aimed to determine the effect of different dietary levels of a Chlorella by-product (CBP) on the growth performance, immune response, intestinal microflora and intestinal mucosal morphology of broilers. In total, 480 one-day-old broiler chickens were randomly allotted to four dietary treatments with four replicated pens consisting of 30 chicks. The basal diet was formulated to be adequate in energy and nutrients. Three additional diets were prepared by supplementing 25, 50 or 75 g/kg of CBP to the basal diet. The diets were fed to the broilers ad libitum for 35 days. Result indicated that increasing inclusion level of CBP improved BW gain (linear, p < 0.05). There was no effect of inclusion level of CBP in diets on total cholesterol, triglyceride, aspartate aminotransferase and alanine aminotransferase levels during the 35 days. Plasma IgG, IgM and IgA concentrations increased (linear, p < 0.05) with inclusion level of CBP in diets. Supplementation of CBP in the diets increased (linear, p < 0.05) the concentrations of Lactobacillus in the caecal content and decreased (linear, p < 0.05) the concentrations of Escherichia coli and Salmonella in the caecal content. Villus height increased (linear and quadratic, p < 0.05) with inclusion level of CBP in diets. Crypt depth increased (quadratic, p < 0.05) with inclusion level of CBP, and a decreased villus height: crypt depth ratio (quadratic, p < 0.05) was observed as inclusion level of CBP in diets increased. The results of the current experiment indicate that dietary supplementation of CBP improves growth performance of birds. Dietary CBP has improving Lactobacillus spp. concentrations in the gastrointestinal tract, plasma immunoglobulin concentrations and intestinal mucosal morphology.

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The calves produced by somatic cell nuclear transfer (SCNT) had identical genetic background except for cytoplasmic transmission molecules, which originated from recipient oocytes. To identify the SCNT calves generated from 3 nucleus donors, genotypes for 16 microsatellite (MS) markers and mitochondrial DNA (mtDNA) polymorphisms were analyzed. Using MS genotypes, the parentage test results were not only classified as the single donor-derived calves but mtDNA sequence variations might also discriminated all SCNT calves within the donor-derived families. Comparing MS genotypes, AI-derived progenies were easily discriminated from each other. However, those genotypes could not supply the useful information for identifying the SCNT calves produced from each donor. Informative sequence variations were detected in several regions including D-loop, 12 S rDNA, and ND5 genes. About 19 nucleotide substitutions found within D-loop allowed individual identification for most SCNT-derived progeny except for 5 individuals. However, further investigation on 12 S rDNA and ND5 genes provided the useful polymorphic information for those 5 individuals. Although the experiment had been carried out to produce SCNT calves without previous investigation of mtDNA polymorphism, polymorphic mtDNA sequences provided interesting information that discriminated individuals, even those from the same donor cells. In addition, we could distinguish the 2nd generations produced by AI combinations using SCNT donors and SCNT progeny as the dams and/or the sires when combined molecular data obtained from MS genotypes and mtDNA polymorphisms were derived. These results suggested that mtDNA polymorphisms might supply the critical information for identification and traceability for SCNT-derived calves when combined with MS data. This work received grant support from the Agenda Program (No. 200901FHT010305191), Rural Development Administration, Republic of Korea.