It is well known that in the current floor pen with deep litter system, day old broiler chickens could benefit from non-starch polysaccharides components in the litter to establish the dynamic microbiota. However, when the intestinal microbiota becomes complex and diversified over time and environmental conditions, long term exposure to faeces and ammonia pollution environments has a higher risk of infection with pathogenic bacteria and parasites.
For decades, chicken enteric disease including necrotic enteritis (NE) and coccidiosis have been controlled by using antibiotic growth promoters (AGP) and coccidiostats. However, due to the development of antibiotic resistance in bacteria and coccidiosis, which is a threat to animal and human health, the use of AGP and coccidiostats has been restricted or banned in the poultry industry. Thus, alternatives production strategies including vaccinations, organic acids, prebiotics, probiotics, essential oils, postbiotics or yeast peptides to control NE and coccidiosis have been explored.
The Glucose Oxidase (GOD) is exogenously produced by specific fungi fermentation to oxidize β-D-Glucose into gluconic acid and hydrogen peroxide, consuming large amounts of oxygen at the same time in the chicken gut. Therefore, it can protect against oxidative stress and directly kill some pathogenic bacteria or Eimeria parasites. Gluconic acid is a kind of organic acid, which acts as an acidifier in the intestine to produce the short chain fatty acids such as butyric acid. GOD also plays an important role in colour development, flavour, texture, and increasing the shelf life of food products. Due to its characteristics of producing natural acid, deoxygenation and sterilization, GOD has been defined in AAFCO list as 70.3 and widely used in animal production.
Recently, the University of New England (UNE) conducted a NE challenging trial to investigate the GOD potentials to ameliorate the impact of NE on chicken performance and intestinal health. The standard, positive controls (PC) were formulated based on wheat-sorghum-soybean meal as the commercial diets. Negative control (NC) chickens were challenged with Eimeria parasites at day 9 and clostridium perfringens at day 14. Another 4 treatments consist of PC or NC diets supplemented with antibiotics, GOD 100 g/MT, 200 g/MT and 300 g/MT, respectively.
The effect of GOD on chicken performance before challenging was shown in Figure 1. It is clearly shown that adding GOD significantly improved chicken body weight gain by 9% and FCR was improved by 10 points. From the growth point of view, AGP supplementation did not show any impact on chicken body weight gain and FCR.
However, during the challenging period (Figure 2), AGP significantly improved the chicken body weight gain and FCR compared with the positive control. Interestingly, during the recovery period (Figure 3) or chickens had the longer-term exposure to faeces and ammonia pollution, chickens in positive control and supplemented with the lowest GOD showed worst performance, but chickens in the negative control showed the best performance, possibly due to that Eimeria challenged birds boomed their immune system for the possible coccidiosis infection. It might also imply that supplementation of GOD could replace both coccidiostat AGP.
However, the lower level of GOD might have the negative effect of Eimeria vaccination.
Figure 1. The effect of GOD on chicken performance before challenging.
Figure 2. The effect of GOD on chicken performance during challenging.
Figure 3. Efeect of GOD on chicken body weight gain after challenging period (d 28-35)