Evaluating portable wire-flooring models for inducing bacterial chondronecrosis with osteomyelitis in broilers.

Rearing broilers on flat or sloping wire flooring is an effective method for consistently triggering lameness attributable to bacterial chondronecrosis with osteomyelitis (BCO). Portable obstacles known as speed bumps (SB) also consistently trigger modest incidences of BCO when they are installed between feed and water lines in litter flooring facilities. Two experiments were conducted to determine the most effective broiler age for introducing the SB into litter flooring pens, and to evaluate alternative configurations of the traditional SB with the expectation that amplified mechanical challenges to the legs of broilers should increase the incidence of BCO. Broiler chicks obtained from commercial hatcheries (lines B and D in experiment 1, lines A and B in experiment 2) were reared in floor pens with ad libitum feed and water and a 23L:1D photoperiod. In experiment 1, the 5 floor treatments included wood shavings litter only (L), flat wire only (W), or litter plus SB installed at 14, 28, or 42 d of age. Line B was more susceptible to lameness than line D (25.9 vs. 15.3% for all treatments combined; P = 0.001). Both lines developed low incidences of lameness on L (11 to 13%), intermediate incidences on SB regardless of day of installation (12 to 23%), and high incidences on W (21 to 39%). In experiment 2, broilers were reared with 7 floor treatments, including L, W, SB with a 50% slope (SB50%); SB50% with a limbo bar installed over the apex; SB with a 66% slope and limbo bar; SB50% with a nipple water line suspended over the apex; and a pagoda-top SB. All SB were inserted on d 28. Line B was more susceptible to lameness than line A (20.2 vs. 16.1% for all treatments combined; P < 0.05), and for both lines combined the lameness percentages averaged 7.7 (L), 29.2 (W), 17.3 (SB50%), 16.2 (SB50% with a limbo bar), 21.5 (SB with a 66% slope and limbo bar), 20.8 (SB50% with a nipple water line), and 11.5% (pagoda-top). These studies demonstrate the portable SB can be effectively used to experimentally trigger BCO in broilers.

Susceptibility of 4 commercial broiler crosses to lameness attributable to bacterial chondronecrosis with osteomyelitis.

Growing broilers on wire flooring provides an excellent experimental model for exposing susceptibility to lameness attributable to bacterial chondronecrosis with osteomyelitis (BCO). Two independent experiments (E1, E2) were designed to compare the susceptibilities of broilers from 4 commercial crosses (W, X, Y, and Z). The standard crosses (W and Y) grow rapidly at an early age, whereas high-yield crosses (X and Z) initially tend to grow more slowly. Chicks were obtained from a commercial hatchery for E1, or were hatched at the University of Arkansas Poultry Research Hatchery for E2. Males and females were reared together (E1; n = 360/cross) or separately (E2; n = 390/cross) in 3 × 3 m pens on litter or wire flooring (wire). Necropsies revealed lesions that were pathognomonic for BCO in ≥94% of the birds that became lame. The SigmaStat Z-test was used to compare cumulative lameness incidences at 8 wk of age. For birds reared on litter, lameness incidences were low and did not differ between crosses or sexes (range: 2.2 to 4.6%; P ≥ 0.6). When males were reared on wire, their lameness incidences (by cross) were E1 = 52% for W(b); 42% for X(c); 69% for Y(a), and 44% for Z(bc); E2 = 31% for W(b); 19% for X(c); 49% for Y(a); and 25% for Z(bc). For females reared on wire, the lameness incidences were E1 = 40% for W(b), 30% for X(c), 49% for Y(a), and 28% for Z(c); E2 = 16% for W; 15% for X; 16% for Y; and 15% for Z (ns). Accordingly, the hierarchical ranking for BCO susceptibility by broiler cross was X ≤ Z ≤ W < Y for males in E1 and E2, for females in E1, and for males and females pooled in E1 and E2. Standard broiler crosses developed higher incidences of lameness than high-yield crosses, implicating an association between rapid early growth and susceptibility to BCO. Rearing the females separately on wire in E2 led to uniformly low incidences of BCO, regardless of cross. Stress-mediated immunosuppression contributes to the pathogenesis of BCO; perhaps female broilers experience less social or competitive stress when reared separately from their male hatch mates.

Divergent selection for relative breast yield at 4 D posthatch and the effect on embryonic and early posthatch development.

Genetic selections for growth promotion in poultry have been highly successful in improving growth, yield, and feed conversion in the modern broiler. These selections have focused on the use of hypertrophy, the increase of muscle fiber size to improve growth. Muscle growth however is not limited solely to hypertrophy but is largely attributable to both hypertrophy and hyperplasia, the increase in muscle fiber number. As muscle fiber size has been theorized to reach an eventual physiological limit, it was determined to develop a novel method of selection focusing on hyperplasia. Divergent selection for 4-day relative breast yield (BY4) was chosen as it is believed to occur at point at which muscle cell number per gram is maximized and satellite cell activity is higher than later in life. Using a random bred control population, divergent selection was undergone for BY4. The 2 broiler lines divergently selected for BY4 are noted as the high and low BY4 lines, respectively (high 4-day breast yield and low 4-day breast yield). Heritability estimates for selection of 4-day breast percentage in the upward and downward directions were 0.63 and 0.44, respectively. Divergent selection resulted in clear divergence in BY4 and shows promise in utilizing BY4 to promote broiler growth and body composition.

Grape powder attenuates the negative effects of GLP-1 receptor antagonism by exendin-3 (9-39) in a normoglycemic mouse model.

Prediabetes is a condition affecting 35% of US adults and about 50% of US adults age 65+. Foods rich in polyphenols, including flavanols and other flavonoids, have been studied for their putative beneficial effects on many different health conditions including type 2 diabetes mellitus and prediabetes. Studies have shown that some flavanols increase glucagon-like peptide 1 (GLP-1) secretion. GLP-1 is a feeding hormone that increases insulin secretion after carbohydrate consumption, and increased GLP-1 secretion may be responsible for some of the beneficial effects on glycemic control after flavanol consumption. The present study explored the effects of grape powder consumption on metrics of glycemic health in normoglycemic and prediabetic C57BL/6J mice; additionally, the mechanism of action of grape powder polyphenols was investigated. Grape powder significantly reduced (p < 0.01) blood glucose levels following oral glucose gavage after GLP-1 receptor antagonism by exendin-3 (9-39) compared to sugar-matched control, indicating that it was able to attenuate the hyperglycemic effects of GLP-1 receptor antagonism. Grape powder was employed in acute (1.6 g grape powder per kg bodyweight) and long-term high fat diet (grape powder incorporated into treatment diets at 5% w/w) feeding studies in normoglycemic and prediabetic (diet-induced obesity) mice; grape powder did not impove glycemic control in these studies versus sugar-matched control. The mechanisms by which grape powder ameliorates the deleterious effects of GLP-1 receptor antagonism warrant further study.