Effect of dietary coarse corn inclusion on broiler live performance, litter characteristics, and ammonia emission.

Ammonia (NH3) emission from nondigested nutrients in poultry creates additional adverse environmental impacts on soil, water, air, and health. Mitigating NH3 emission has become vital for the poultry industry to remain sustainable. As the presence of large particles in the feed stimulates the broiler gizzard to retain ingesta in the gastrointestinal tract longer and improve digestive efficiency, the inclusion of large particles in feed may lead to less nitrogen (N) and moisture content (MC) in feces such that lower NH3 production would be expected. This chamber study investigated the effects of dietary coarse corn (CC) inclusion on broiler live performance, litter characteristics, and NH3 emission. One hundred eighty female broilers (Ross 344 × 708 strains) at day 21 were randomly placed in 6 chambers with 2 dietary treatments (0% CC and 50% CC), with 3 chambers per treatment and 30 birds per chamber for 3 wks. The results showed that the 50% CC inclusion (1) decreased broiler feed intake and BW without affecting mortality-adjusted feed conversion ratio from day 21 to 42; (2) increased gizzard weight and decreased proventriculus weight; (3) decreased N content and MC in litter; and (4) decreased NH3 concentrations in the chambers, as well as NH3 emission from the chambers. Dietary CC inclusion could be an effective way to mitigate broiler litter N content and MC as well as NH3 emission.

Effect of Limestone Particle Size and Potassium Supplementation on Growth Performance, Blood Physiology, and Breast Muscle Myopathy of Male Broiler Chickens.

The experiment investigated the effects of limestone particle size and dietary potassium (K) on live performance, blood physiology, and muscle myopathies in broilers raised to 35 days of age. A total of 384 Ross male broilers were placed in 24 floor pens and fed four diets during the starter (0-16 days of age) and grower (17-33 days of age) periods containing two limestone particle sizes (fine: 0.2 mm and coarse: 0.9 mm), and amended with either 0% basal K (K-) or 0.2% added dietary K (K+) as potassium carbonate to complete the 2 × 2 factorial arrangement. Live performance was measured from 1-33 days of age. Blood physiology, woody breast (WB), and white striping (WS) scores were measured at 35 days of age. The K+ dietary treatment reduced (P < 0.05) feed intake and BWG when compared to K- during the starter and grower period. The K+ dietary treatment decreased blood Na (mmol/L), blood glucose (mg/dl), ionized blood Ca (mg/dl), TCO2 (mmol/L), blood HCO3 (mmol/L), and base excess in extracellular fluid (mmol/L) when compared to K- birds of similar body weight at 35 days of age (P ≤ 0.05). Fine limestone diets tended to reduce WB scores (3.0 vs. 2.59) when compared to coarse limestone diets at 35 days of age (P = 0.08). This study demonstrated that using 0.2% of K as potassium carbonate did not negatively affect FCR even though FI and BWG were reduced. Furthermore, fine limestone has the potential to reduce WB in breast muscle tissues; however, further research is needed to confirm these outcomes.

Phenotypic and genotypic heterogeneity among Streptococcus iniae isolates recovered from cultured and wild fish in North America, Central America and the Caribbean islands.

Streptococcus iniae, the etiological agent of streptococcosis in fish, is an important pathogen of cultured and wild fish worldwide. During the last decade outbreaks of streptococcosis have occurred in a wide range of cultured and wild fish in the Americas and Caribbean islands. To gain a better understanding of the epizootiology of S. iniae in the western hemisphere, over 30 S. iniae isolates recovered from different fish species and geographic locations were characterized phenotypically and genetically. Species identities were determined biochemically and confirmed by amplification and sequencing of the 16S rRNA gene. Repetitive-element palindromic PCR fingerprinting as well as biochemical and antimicrobial susceptibility profiles suggest that a single strain of S. iniae was responsible for two different disease outbreaks among reef fishes in the Caribbean, one in 1999 and another in 2008. Interestingly, a majority of the isolates recovered from cultured fish in the Americas were genetically distinct from the Caribbean isolates and exhibited a trend toward higher minimal inhibitory concentration with respect to several antibiotics as well as greater genetic variability. The biological significance of this genetic variability is unclear, but it could have implications for future vaccine development and treatment.