Field trial to study the possibilities of using probiotic bacteria in drinking water replacing antibiotics/growth promoters in feed during broiler rearing and to investigate the effect of catalyst activated water (CAW) when combined with the probiotic in drinking water

Antibiotics are commonly used in food animals to promote growth and prevent disease, as well as to treat sick animals. This has led to the development of antibiotic resistant pathogens and subsequently different countries have banned the use of antibiotics as growth promotion (AGPs). To eliminate the use of AGPs and to maintain animal productivity, some farmers have been using live microorganisms in the feed as feed supplements which beneficially affects the host animal by improving its intestinal microbial balance. Benefits from probiotic microorganisms have been recognized for over 100 years, and as being useful in poultry for about 50 years. The most commonly used probiotic microorganisms include members of lactic acid bacteria (LAB), like Lactobacillus spp., Bifidobacteria spp. and Saccharomyces spp.  which do not produce heat resistant spores and vegetative stages of these species are easily destroyed by the heat applied during the feed manufacturing process.

Bacillus species are gram positive, rod shape bacteria that are strict aerobes or facultative anaerobes which produce heat resistant spores under stressful conditions. Though the soil is considered the habitat, several studies have shown that Bacillus spores can be found in the intestinal tracts of animals where they live and multiply actively. There is enough literature to suggest that the Bacillus spp. is commensal bacteria of the gastrointestinal tract. Though, there are published literature on the performance of broilers with feed supplemented with spores Bacillus spp., there is hardly any on the use of Bacillus probiotic bacteria delivered via broiler drinking water and the present study was to study the possibilities of replacing the use of antibiotic/ growth promotors in the feed and delivering a mixture of Bacillus species through drinking water. Also, tested the effect of catalyst activated water on the broiler performance.    

Day old cull (unhealed naval) broiler chicks obtained from a reputed hatchery operator in Sri Lanka were used for the trial. Chicks were randomly grouped into four groups, each group having 31 chicks. Three groups were used as treatments; T1, T2 and T3, and one group was used as the control (positive control). Conventional open house rearing with bird space of one square foot per bird was employed. The feed used for the treatment groups was free from antibiotics/growth promoters and the drinking water was free from chlorine. The birds in the control group received normal feed which was available for the other broiler farmers containing antibiotic/growth promoters. Drinking water for the control group was treated with chlorine (2 mgL-1). Chicks in the control group were administered through drinking water with an antibiotic during the first 3 days. The probiotic bacterial count of the water for the three treatments was 2.44 x 103 CFU ml-1. The CAW was diluted according to the instructions given on the bottle (200 ml of CAW to 1000 liters of water). The four groups of birds received treatment as given in table1.

Table 1. Treatments of the four group of chicks ( + treated, - not treated)

Birds were weighed weekly, mortality and the feed conversion ratios were calculated at end of the trial, 42 day period. Analysis of variance (ANOVA) was carried out to find out whether the growth of birds of treatments groups was different from those of positive control group.

Figure 1 shows the average weekly growth of birds of different groups and the growth differences were not significant from each group.

Fig. 1.  Effect of probiotic bacteria and CAW given through drinking water on the average growth of broiler birds compared to positive control. (T1 – Probiotic, T2 – Probiotic + CAW, T3 - CAW, Positive Control – Feed with antibiotics/growth promoters & chlorinated water). 

Fig. 2.  Effect of probiotic & CAW on FCR compared to positive control; (T1 – Probiotic, T2 – Probiotic + CAW, T3 - CAW, Positive Control – Feed with antibiotics/growth promoters & water chlorinated water). 

The highest FCR was observed (2.13) for the positive control group while the lowest (1.97) was for both T2 & T3 groups. The group that received only probiotic had an FCR of 2 (Fig.2).

Fig. 3. Effect of probiotic &CAW on the mortality of broiler birds compared to positive control; (T1 – Probiotic, T2 – Probiotic + CAW, T3 - CAW, Positive Control – Feed with antibiotics/growth promoters & water chlorinated water).

The highest % mortality (12.91%) was recorded for the positive control group (chlorinated water, no probiotic bacteria in drinking water, feed containing antibiotics/growth promoters) while all the three treatment groups had percentage mortality of 3.23% (Fig. 3).

The two groups of chicks that were treated with the probiotic bacteria had wet litter during the first three days which slowly disappeared after 3 days but the chicks took feed and water normally during the wet litter period.