A tolerance test associated with efficacy study 1 was provided by the applicant. Animals were divided in four groups: control and three treatment groups, providing C.butyricum kg feed at doses of 5 x 10⁸ , 5 x 10⁹ and 5 x 10¹⁰ (100X the recommended dose) CFU/ kg complete feed,. The study was made using diclazuril and monensin in grower (1-21 days of age) and finisher (22-42 days of age) periods, respectively.

The zootechnical parameters of one-day-old to 42-day-old animals were recorded. Blood samples were obtained from ten males and ten females per treatment at the end of the trial (day 43), and haematological (haematocrit, haemoglobin, mean corpuscular haemoglobin concentration, leucocytes and differential leucocyte counts) and biochemical parameters (serum aspartate amino transferase, alanine aminotransferase, gammaglutamine transpeptidase, uric acid, albumin and total proteins) were analysed. The data were analysed using an ANOVA test. Mortality was less than 2 % and not treatment-related. Performance was not adversely affected by the overdose of Miya-Gold®S (see Table 2). None of the blood parameters were significantly affected by the inclusion of CBM 588 in the feed.

Faecal samples were taken at 21 and 42 days of age. The counts of CBM 588 increased in faeces as the dosage of C.butyricum increased in feed. No significant differences were detected between treatments for C. perfringens and E. coli counts on faecal samples taken on day 42.

Conclusions on

As no adverse response was seen when C.butyricum was included in diets at 100 times the recommended dose, the FEEDAP Panel concludes that the product is safe for chickens for fattening at the recommended dose.