Morphometric Documentation of a High Prevalence of Left Ventricular Dilated Cardiomyopathy in Both Clinically Normal and Cyanotic Mature Commercial Broiler Breeder Roosters with Comparisons to Market-Age Broilers.

Previous studies documented the common occurrence of transitory cyanosis and echocardiographic aortic insufficiency in mature commercial broiler breeder roosters. During further investigations, we observed a high prevalence of hearts exhibiting extensive dilation of the left ventricle chamber compatible with dilated left ventricular cardiomyopathy present in both cyanotic and normal subpopulations. We conducted quantitative studies focused on documentation of cardiac ventricle parameters by using simple gross morphometric methods performed on formalin-fixed hearts obtained from both clinically normal roosters and those exhibiting variable transitory cyanosis, echocardiographic aortic insufficiency, or both. A high prevalence of often dramatic left ventricular dilation reflected in enlarged left ventricular chamber areas and elevated left ventricle-to-total ventricle area ratios was morphometrically documented. However, no statistically significant differences in the occurrence of ventricular abnormalities were observed between normal and cyanotic roosters. Age-associated changes were also demonstrated by comparative morphometric studies on hearts from normal market-age broilers (average age of 7 wk) and those of mature roosters (average age of 42 wk). Elevation in both left and right ventricular weight-to-total heart weight ratios dramatically increased with aging. In addition, values (average ± SD) for the left ventricle chamber area-to-total ventricle area ratios increased from 3.2 ± 2.0% in broilers up to 10.0 ± 8.8% in roosters. None of the normal broilers studied demonstrated left ventricular volume ratios above 10%, whereas 33% of the roosters had left ventricular volume ratios above 10%, including 13% with ratios of 20% or higher. However, the left ventricle wall area-to-body weight ratios were much closer for the two age groups (0.85 ± 0.18 cm(2)/kg in broilers and 0.79 ± 0.13 cm(2)/kg in roosters). Also, the standard right ventricle-to-total ventricle weight ratio (RV/TV) went from 0.18 ± 0.04 in broilers to 0.25 ± 0.12 in roosters, whereas the left ventricle-to-total ventricle weight ratios were similar for the two age groups (0.74 ± 0.12 and 0.75 ± 0.08 in broilers and roosters, respectively). Our results for RV/TV in normal broilers were similar to the reported values for normal market-age broilers. In contrast, 36% of the roosters had RV/TV above values reported for broilers considered reflective of right ventricular hypertrophy due to pulmonary hypertension, whereas 4% had values above the reported threshold for broilers dying with ascites (ratios greater than 0.0249 and 0.299, respectively). However, ascites was not observed for any of the roosters. Although essentially all cardiac morphometric parameters demonstrated statistically significant correlations with the age-class group comparisons, significance could not be documented for comparisons between cardiomorphometrics and the subjective occurrences of transitory cyanosis or echocardiographic aortic insufficiency.

In vivo safety and tolerability study of QR-441(a) using three dose formulations and three routes of administration in chickens.

The current study assessed the safety, tolerability, and palatability of the experimental drug QR-441(a) using three dose formulations and three routes of administration. A 4-day study was carried out using a total of 132 chickens. A total of 11 groups were formed (12 chickens per group) subjected to varying concentrations and routes of administration of QR-441(a). Chickens were given a high, medium, or low dose of QR-441(a) in either feed, water, or both for a period of 4 days. In addition, one group was dosed intranasally, one drop per nostril four times a day. Although no lesions were found to suggest toxicity or irritability, the medium- and high-dose water groups reduced their water intake. This reduction in water intake suggests that chickens may find the medium and high water doses unpalatable. There was no reduction in water intake in the low-dose water groups or in any of the formulated feed groups. There was also no evidence of toxicity or irritability in the nasal-dose group. These data support the use of the low, medium, and high doses in feed and the use of the low-dose concentration in water for the administration of QR-441(a). The data also suggest that QR-441(a) can be administered intranasally without the presence of any adverse events.

Stakeholder position paper: poultry.

There has been renewed concern in recent years about the use of antibiotics in food animal production and the potential risk it may pose to public health due to transfer of antibiotic resistance factors via the food supply. Although a legitimate concern, it bears reminding that this debate is not new. It has been ongoing for decades, yet there is still no documented case of human treatment failure due to antibiotic resistant bacteria acquired from USDA-inspected meat and poultry. This fact strongly suggests that the issue is not the imminent threat as has been portrayed by certain individuals or advocacy groups. The poultry industry as a whole has been using antibiotics responsibly for several decades, and there are strong beneficial arguments for their continued use. Responsible public policy demands a science-based approach be utilized in the decision making process before attempting to restrict or remove certain products due to overestimated risks. Part of this scientific review should include antibiotic use data, however this information has definite limitations and shortcomings which need to be understood before attempting to make any valid antibiotic resistance associations.