Rapid growth predisposes broilers to necrotic enteritis

Abstract

Over the past 50 years, intentional genetic selection within the broiler industry has led to major improvements in both body weight gain (BWG) and feed conversion efficiency. Next to its economic advantages, enhancing BWG can increase the risk for metabolic and skeletal disorders. The aim of this study was to examine whether higher BWG is a predisposing factor for broiler necrotic enteritis. In this study, 300 broilers were challenged with Clostridium perfringens using a well-established, previously described challenge model. It was found that birds with a higher body weight (BW) and BWG before challenge were predisposed to develop more severe necrotic enteritis lesions. After challenge, the average BWG of the birds developing mild to severe lesions dropped significantly, negatively affecting animal welfare and performance. These results show a significant interplay between BWG and the development of necrotic enteritis lesions. This raises the question whether there is a limit to broiler performance with respect to maintaining intestinal health, and whether decreasing BWG (at certain stages of the growth cycle) can be part of a plan to prevent intestinal pathology. Research highlights Higher body weight is a predisposing factor to necrotic enteritis in broilers.

Effect of Feed Additives as Alternatives to In-feed Antimicrobials on Production Performance and Intestinal Clostridium perfringens Counts in Broiler Chickens

“…Disease conditions associated with increased metabolism and rapid growth in broilers (in particular cardiovascular and musculoskeletal disorders) are generally important, and it has been claimed that such conditions cause greater economic loss than infectious agents [41]. In a recent study, it was found that chickens with higher body weight and BWG were predisposed to develop more severe NE lesions when challenged with CP [42]. Although attractive in the short run, increased weight gain may therefore come at a cost not only to chicken health and welfare but also to the farmers' economy and a sustainable use of feed resources.…”

Re-calculating the cost of coccidiosis in chickens

“…Recalculating the figure using prices from 2016, including costs associated with vaccination, indicate a financial cost of £99.23 million per annum, 95.1% of which derived from broiler production. The notable increase in cost can be explained in part by the larger chicken population and currency inflation, although costs associated with broiler prophylaxis and impacts on growth (reduced weight gain and increased FCR) were notably higher, likely amplified by the considerable genetic progress achieved by the primary breeding companies in selection for faster growing and more feed-efficient broiler stock [ 20 ]. The increased cost of coccidiosis may also have been influenced by the withdrawal of antibiotic growth promoters (AGPs) from chicken diets.…”

“…Poultry production has undergone considerable development over the last 25 years. Broiler growth rates have increased, feed conversion ratios (FCR) fallen and average days to market reduced in intensive systems [20]. Similarly, egg production has changed including longer, more productive laying cycles [21].…”

Anthropogenic suffering of farmed animals: the other side of zoonoses

“…Similarly, in broiler chickens (European Commission 2016, Dinev et al 2019, Hartcher & Lum 2020, unnaturally rapid growth and excessive muscle mass can cause pathologies including tibial dyschondroplasia and vertebral abnormalities such as spondylolisthesis, which are associated with neurological disorders (paresis, paralysis) and angular deformities of the feet (valgus, varus) (Makrai et al 2011, Aitchison et al 2014, Jung et al 2018, Huang et al 2019, Guo et al 2019. Genetic abnormalities (Dierick et al 2019) also cause pathologies at sites other than the arthro-skeletal system, notably hypertrophic cardiomyopathy (in both chickens and turkeys, due to too-rapid growth, high metabolic rate and excessive stress), which can lead to sudden death (Chen et al 2017;Olkowski et al 2020). Obstetrical problems resulting from fetopelvic disproportion occur in some species of beef cows with artificially exaggerated muscle mass, who cannot give birth naturally and must always deliver their calves, too large to pass through the pelvic canal, by caesarian section (Greger 2010;Waldner 2014;Pearson et al 2019).…”