Efficacy of CLOSTAT™ as a replacement for antibiotics in swine - a farm trial in Vietnam
Swine producers around the world including Vietnam are working to reduce the reliance on antibiotics. CLOSTAT™ containing a specific strain of B. subtilis PB6, was used in a 2 stage farm trial in Vietnam where the objective was to replace colistin. In stage 1, pigs were weaned at 4 weeks and moved to pens with feed containing the farm’s normal antibiotic regime to 11 weeks, ie. colistin, amoxicillin, tiamulin and florphenicol – this was the control group. The treatment group was this same feed but with colistin removed and replaced by CLOSTAT™ from 4-11 weeks of age. In stage 2 of the trial, the normal farm antibiotic control regime from stage 1 with florphenicol continued in feed through to 24 weeks of age was compared with 2 groups of pigs that received feed containing CLOSTAT™ from 5 days of age through to 26 weeks, but remained in sow farrowing crates from weaning at 4 weeks to 7 weeks of age (these 2 groups of pigs also received tylosin to 15 weeks of age). Pigs receiving CLOSTAT™ instead of colistin in stage 1 were significantly heavier at 11 weeks by 1.6kg with a 5.8% faster growth rate from weaning. When the normal antibiotic control group from stage 1 was compared with the CLOSTAT™ groups in stage 2, the growth rate of the CLOSTAT™ groups was 17 and 20% and faster and with significantly less diarrhoea to 11 weeks of age as well as no loss in growth rate to finishing weight.The results are discussed in relation to the use of CLOSTAT™ along with altered weaning management practice.
Swine producers around the world, including in Vietnam, are assessing ways to reduce antibiotic use and reliance.Bacterial resistance is a global problem with the regular use of antibiotics (Chalmers et al, 2008). The risk of inadvertent antibiotic residues in meat also remains a concern.
CLOSTAT™ HC Dry contains 4 x 1011 cfu/kg of Bacillus subtilis PB6.B. subtilis PB6 exhibits in vitro activity against Clostridium perfringens (Teo & Tan, 2005) including swine isolates of C. perfringens and C. difficile (Kemin Technical Literature, 2009). Necrotic enteritis challenge studies in broiler chickens have shown CLOSTAT™ to be effective and comparable with antibiotics (Boren et al, 2007). B. subtilis PB6 has also produced positive effects on intestinal villous structure in mice (Foligne et al, 2012) and in broiler chickens (Jayaraman et al, 2013; Abudabos et al, 2013; Al-Fataftah & Abdelqader, 2014), as well as desirable immune responses (Selvam et al, 2009; Melegy et al, 2011) and improvements in growth performance in broiler chickens under heat stress (Al-Fataftah & Adbelqader, 2014).
The use of CLOSTAT™ has resulted in improvements in weight gain and feed conversion efficiency in weaned pigs (EFSA, 2012), improvements in weight gainand mortality in suckling piglets (Hanson et al, 2009),and improvedreproductive performance in sows (Kemin Technical Literature, 2010).
The farm trial described herewas conducted with pigs in 2016 in the Binh Duong Province of Vietnam to assess the efficacy of CLOSTAT™ in replacing colistin from weaning (4 weeks) to 11 weeks of age,and also to assess the response from CLOSTAT™ in feed from 5 days of age to finishing weight at 26 weeks.
All diets were based on corn, wheat, rice bran and soybean meal.This farm trial was conducted in 2 stages. The antibiotic and CLOSTAT™ HC Dry regimes for stage 1 and stage 2 are shown in Table 1.
The control feed contained 180ppm of colistin, 300ppm of amoxicillin, and 150ppm of tiamulin from 5 days of age through to weaning at 4 weeks and then up to 9 weeks of age. From 9 to 11 weeks of age, this control feed contained 180ppm colistin and 40ppm florphenicol. The treatment feed was the same as the control feed, except it did not contain colistin at any stage, but did contain 500ppm of CLOSTAT™ HC Dryfrom weaning at 4 weeks to 11 weeks.Body weight, daily weight gain, feed conversion ratio and mortalities were recorded through to 11 weeks of age.
Stage 2: The control group from stage 1 was used as the control treatment in stage 2 and continued to receive 40ppm of florphenicol from 11 weeks through to 24 weeks of age.The period from weaning to finish was 149 days.Two other groupsof pigs (98 and 97 pigs) were weaned at 4 weeks, but remained in the sow farrowing crates until 7 weeks of age, and were then transferred to nursery pens where live weight and sex were balanced across pens. These 2 groups received 500 ppm of CLOSTAT™ HC Dry and 110ppm of tylosin per tonne of feed from 5 days of age to 15 weeks and then 500ppm of CLOSTAT™ HC Dry without any antibiotics through to finish.The period from weaning to finish in these groups was 155 days.Body weight, daily weight gain and feed conversion ratio were recorded throughout the trial period. The incidence of diarrhoea (daily observations for soft, watery faeces) was recorded during the period from weaning to 11 weeks.
Table 1. Antibiotic and CLOSTAT™ HC Dry regimes for stage 1 and stage 2
The results from the first stage of the trial for the control (i.e. antibiotic regime) and the treatment group (i.e. colistin replaced by CLOSTAT™) for the period from weaning to 11 weeks are shown in Table 2.
Table 2. Stage 1 - pig performance from weaning (4 weeks) to 11 weeks of age
The removal of colistin and its replacement with CLOSTAT™in the treatment group did not result in decreased growth rate or feed conversion, but instead the 11 week body weight was significantly higher for the CLOSTAT™treatment group with pigs being 1.6kg heavier on average which was associated with a 5.8% faster growth rate.There were 6 pig deaths with all deaths ascribed to complications from a live PRRS (porcine reproductive and respiratory syndrome) vaccine administered 3 days after weaning.
Table 3 shows the comparative pig performance results for stage 2 of the trial through to finishing weight for the continued control group from stage 1 and the two CLOSTAT™ groups of pigs.
Table 3. Stage 2 - pig performance from weaning to finish weight
No statistical analysis was done on the data from stage 2 becausethe control group and the other 2 groups were not grown outsimultaneously. However, these data do indicate that CLOSTAT™from 5 days to finish combined with tylosin to 15 weeks of age could replace colistin, amoxicillin, tiamulin and florphenicol as shown by numerical improvements in growth rate, particularly from weaning to 11 weeks, i.e. +17 to +20%. Note however that weaned piglets in the CLOSTAT™ groups remained in sow farrowing crates for 3 weeks after weaning compared with the transfer of piglets from farrowing crates to nursery pens at weaning for the control group. It is also noteworthy that the diarrhoea incidence for the critical period from weaning to 11 weeks was considerably less for the CLOSTAT™ plus tylosin groups compared to the group that received colistin, amoxicillin, tiamulin and florphenicol (Figure 1).Whilst the 4 to 11 weekgrowth improvement for the two CLOSTAT™groups was not fully maintainedthrough to finish, there was no growth rate reduction, i.e. +4% and 0%average daily gain for Group 1 and 2 respectively.
Removing colistin from the antibiotic regime and replacing it with CLOSTAT™ in stage 1 resulted in no loss of growth or feed conversion performance to 11 weeks of age. Indeed, pigs on the CLOSTAT™ treatment were significantly heavier at 11 weeks by 1.6 kg (i.e. +4.8%).There was also no loss in growth rate when CLOSTAT™was included in feed from 5 days of age through to finishing weight in Stage 2 compared with the control antibiotic regime from Stage 1.
Comparing the weaning to 11 week diarrhoea results for the farm’s normal antibiotic programme with the two groups that received CLOSTAT™ and tylosin (Figure 1), pigs receiving the probiotic exhibited a lower incidence of diarrhoea. However, pigs in the CLOSTAT™ treatment groups remained in sow farrowing crates for 3 weeks post-weaning which may have contributed to this outcome. Antibiotic reduction programmes are likely to require concomitant altered management practices.Antibiotic resistance cannot be excluded from contributing to the higher diarrhoea incidence recorded for the control antibiotic group with the antibiotic regime having been used on the farm for a number of years.
1. CLOSTAT™ successfully replaced colistin to 11 weeks of age;
2. CLOSTAT™ and altered weaning management were associated with improved pig growth and reduced diarrhoea.
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Article made possible through the contribution of Tinh Nguyen, Rick Carter and Kemin Animal Nutrition and Health (Asia)