A study was conducted to evaluate the effect of supplemental yeast culture (Diamond V XP Yeast Culture; YC) in broiler diets on performance, digestibility, mucosal development, and immunomodulatory functions. One-day-old Arbor Acres chicks (n = 960) were randomly assigned to 1 of 4 dietary treatments based on corn and soybean meal and containing 0, 2.5, 5.0, and 7.5 g/kg of YC in the diet for 42 d. Each treatment consisted of 12 replicates of 20 broilers each. Nutrient digestibility was determined on d 15 and 35 by total fecal collection. On d 21 and 42, 12 birds per treatment were sacrificed to evaluate gut morphology and secretory IgA. Broilers were vaccinated with Newcastle disease vaccine by eye drop on d 7 and 28 and antibody titer was determined on d 14, 21, 35, and 42. Dietary supplemental YC at 2.5 g/kg improved average daily gain and feed conversion during grower and overall periods (P 0.05) protein retention and energy digestibility. Villus height to crypt depth ratios in the duodenum and jejunum (d 42) and ileum (d 21) were increased (P

The effect of transport stress on blood metabolism, glycolytic potential, and meat quality in broilers was investigated. Arbor Acres chicks (n = 360, 1 d old, males) were randomly allotted to 1 of 5 treatments: unstressed control, 45-min (short-term) transport with 45-min (short-term) recovery, 45-min transport with 3-h (long-term) recovery; 3 h (long-term) transport with 45-min recovery, and 3-h transport with 3-h recovery. Each treatment consisted of 6 replicates with 12 birds each. On d 46, all birds (except the control group) were transported according to a designed protocol. Transport time affected plasma glucose level (P<0.05) and glycogen level (P=0.06) in breast muscle as well as the area (P<0.01) and density (P<0.01) of IIa fibers. Glucose concentration increased slightly during the first 45 min of transport and then decreased dramatically in the long-term transported broilers (P<0.05). Long-term transport decreased the concentration of breast glycogen (P=0.06) and affected the size of IIa fibers in tibialis anterior by decreasing the area (P<0.01) with an increase in density (P<0.01). However, a long-term recovery after transport contributed to the homeostasis of blood corticosterone (CORT, P=0.05) and low levels of glycogen (P<0.05), lactate (P<0.01), and glycolytic potential (P<0.01) in thigh muscles. Interactions existed between transport and recovery time on area (P<0.05) and density (P<0.01) of IIa fibers. Furthermore, plasma nonesterified fatty acids increased significantly in the 3-h transport with 3-h recovery group (P<0.05) in comparison with the control. These results suggested that transport induced the release of plasma CORT and glycopenia, which affected the contractive status of muscle fibers by changing their area and density, and enhanced glycolysis and even lipolysis. A long-term recovery after transport was beneficial in lowering plasma CORT levels and reducing muscle glycolysis, which might improve broiler meat quality.

Knowledge about the modulation of gut microbiota improves our understanding of the underlying mechanism by which probiotic treatment benefits the chickens. This study examined the effects of Bacillus subtilis DSM 32315 on intestinal structure and microbial composition in broilers. Broiler chicks were fed basal diets without or with B. subtilis supplementation (1.0 × 109 spores/kg of diet). Supplemental B. subtilis increased average body weight and average daily gain, as well as elevated villus height and villus height to crypt depth ratio of ileum in broilers. Multi-dimension analysis showed a certain degree of separation between the cecal microbiota from treatment and control groups. Increased Firmicutes abundance and reduced Bacteroidetes abundance in cecum were observed responded to B. subtilis addition, which also increased the abundances of Christensenellaceae and Caulobacteraceae, and simultaneously decreased the abundances of potentially harmful bacteria such as Vampirovibrio, Escherichia/Shigella and Parabacteroides. Network analysis signified that B. subtilis addition improved the interaction pattern within cecal microbiota of broilers, however, it exerted little influence on the metabolic pathways of cecal microbiota by comparison of the functional prediction of metagenomes. In conclusion, supplemental B. subtilis DSM 32315 improved growth performance and intestinal structure of broilers, which could be at least partially responsible by the manipulation of cecal microbial composition.