Influence of chlorine added to drinking water during the preslaughter feed withdrawal on microbiology and morphology of the broiler gastrointestinal tract

Abstract

The objective of this experiment was to test the effects of the addition of chlorine to broiler drinking water during a 12-h preslaughter feed withdrawal period on reduction of the quantities of microorganisms, such as Escherichia coli and enterococci, in broiler crops and ceca. Reduction of these microorganisms would likely also reduce contamination of broiler meat by pathogenic bacteria during processing. It was also investigated if the chlorine caused some intestinal damage that could disseminate the microorganisms to the carcass. A total of 40 Cobb male broilers were used. Samples of crop and cecal content were collected for microbiological analysis, and duodenum and jejunum were used for morphological analysis from 10 birds in each treatment. The most probable number (MPN) of E. coli and enterococci in the collected samples of crop and ceca and the measure of the free residual chlorine in water were determined. The scanning electron microscopy from duodenum and jejunum was used to illustrate the mucosa integrity. The chlorine added to water was efficient in reducing the quantities of microorganisms in broiler crops and improved the integrity of the mucosa. Therefore, preslaughter feed withdrawal should be coupled with crop disinfection, because preslaughter feed withdrawal increases the MPN of enterococci and E. coli in broiler crops. So, it presents a higher risk for carcass contamination during slaughterhouse processing and, consequently, a higher risk for public health.

Reviewing Interventions against Enterobacteriaceae in Broiler Processing: Using Old Techniques for Meeting the New Challenges of ESBLE. coli?

“…In general, feed withdrawal of 8 to 10 hours is used to reduce the fecal amount in the gastrointestinal tract of broiler chickens and therefore a reduced probability of fecal contamination during automated evisceration is assumed [ 34 , 35 ]. However, in four different studies from three different countries, various outcomes were observed [ 33 , 36 – 38 ]. Results showed both a reduction and an increment of the E. coli amount on the carcasses in the different samplings suggesting insufficient effectiveness of the feed withdrawal concerning the reduction of E. coli .…”

“…In addition to feed withdrawal times, certain feed and water additives were investigated to enhance a possible positive effect of the feed withdrawal concerning the reduction of particular pathogens ( Table 1 ). Substances like specialized replacement finisher [ 37 ], the supplementation of feed with a glucose cocktail [ 39 ], chlorine additives [ 36 ], or magnesium sulfate [ 40 ] in drinking water, or the supplementation of tap water with an allostatic modulator [ 38 ] were investigated. These substances were applied to broiler chickens prior to feed withdrawal.…”

“…Again, various outcomes concerning a reduction of E. coli , Enterobacteriaceae, or coliforms concentrations on broiler carcasses were observed. Glucose feed additives and chlorine compounds in drinking water showed reductions of Enterobacteriaceae or E. coli in chicken crops [ 36 , 39 ]. However, an impact on the reduction of E. coli on the broiler carcasses during processing and concerning the prevention on cross-contamination seemed to be ambiguous and needs further investigations.…”

Growth performance and cecal microbiota of broiler chicks as affected by drinking water disinfection and/or herbal extract blend supplementation

“…Therefore, we considered that providing broiler chicks with chlorinated drinking water was beneficial to decrease the abundance of harmful bacteria in cecum, and therefore benefited to improve the growth performance. Similarly, Barreiro et al (2012) reported that drinking water treated with chlorate reduced the pathogens counts in the intestine. Byrd et al (2003) noted that drinking water administrated with chlorate was able to reduce the contamination of Salmonella in the flock of broiler chick.…”

“…Compared with the above methods, chlorinated drinking water is a common method in animal husbandry because it is easy to disperse, low in cost, and has a wide antimicrobial spectrum ( Tsai et al, 1992 ; Maes et al, 2019 ). Its safety and effectiveness have been fully documented ( Byrd et al, 2003 ; Barreiro et al, 2012 ). Sodium dichlorocyanurate has been approved by the United States Environmental Protection Agency and the WHO for the routine treatment of drinking water.…”