The effect of gluconic acid on growth and intestinal microflora of weanling pigs (Einfluss von Gluconsäure auf Wachstum und intestinale Mikroflora von Absetzferkeln). G. Biagi*, E. Vezzali, A. Piva and F.X. Roth – Bologna/Freising-Weihenstephan The finding that antibiotics fed to farm animals as growth promoters can be responsible for the spreading of resistant bacteria and the consumer demands for a food chain free of drugs determine the need to study alternative strategies to control microbial activity in the gastrointestinal system of monogastric animals. Gluconic acid (GA) has been shown to reach the large intestine in rats where it can be fermented by the microflora (1). Aim of this study was the evaluation of the effect of feeding GA on piglet growth and intestinal microflora. Methods: Immediately after weaning, 48 piglets were divided into 4 groups (12 animals per group, housed in individual cages) for a 6 week trial. Treatments were a commercial diet with a) no addition (control diet) or with b) 0.3%, c) 0.6%, and d) 1.2% of GA. Feed and water were provided ad libitum. Animals were weighed every week and feed consumption was recorded. At day 10 and 31, faecal samples were collected from 6 animals per group and cultured for viable bacteria (coliforms, clostridia and lactobacilli). At the end of the trial, 4 animals per group were killed. Samples of jejunum and caecum content were cultured for viable bacteria and their ammonia and volatile fatty acids (VFA) content as well as pH were determined. Results: Feeding 0.3 and 0.6% of gluconic acid increased average daily gain (ADG) compared to control (P < 0,10), while gain to feed ratio (GF) was not influenced by treatments (Table 1). Faecal bacterial counts after 2 weeks did not show any differences. At week 5, coliforms were markedly reduced by the 0.3% GA treatment compared to control (P < 0.10) and all GA diets showed a tendential increase of the number of lactobacilli. In the caecum, clostridia were significantly reduced by GA at 0.6 and 1.2% (P < 0,10). As previously observed in the faeces, lactobacilli were tendentially increased in the caecum by GA. Ammonia concentration in the intestinal samples was not influenced by treatments. VFA in the intestine were increased by GA, but the differences observed did not reach the significance level due to the high variability. Interestingly, GA mainly increased acetic acid in the jejunum and butyric acid in the caecum. Table 1. Live weight, average daily gain (ADG), daily feed intake and feed to gain ratio (FG) of piglets in the 6 weeks after weaning. Values are means of 12 animals ± SD. Final live weight ADG Daily feed intake FG (kg) (g/d) (g/d) Control 25.08 ± 3,09 423 ± 67 704 ± 121 1.67 ± 0.06 Gluconic acid 0.3% 26.73 ± 2,73* 464 ± 55* 754 ± 108 1.62 ± 0.07 Gluconic acid 0.6% 26.85 ± 2,95* 466 ± 71* 749 ± 94 1.62 ± 0.08 Gluconic acid 1.2% 25.25 ± 2,22 428 ± 52 696 ± 68 1.63 ± 0.06 *Different from control by P < 0.10. Conclusion: The present results show how feeding GA can improve the growth performances of piglets after weaning. Nevertheless, when used at a high concentration (1.2 %) the positive effect of GA was not observed. The bacterial counts and the VFA analyses show that GA may influence the composition and the activity of the intestinal microflora. Further studies will be needed to achieve a better understanding of the mode of action of GA in pigs. 1) ASANO, T, YUASA, K, YOSHIMURA, Y, TAKENAWA, S and FUKUBA, H (1997): J. Jpn. Soc. Nutr. Food Sci. 50, 287-294. _______________________ *Department of Physiology and Animal Production, Faculty of Veterinary Medicine, University of Bologna, Via Tolara di Sopra 50, I-40064 Ozzano Emilia
Biagi G., Vezzali E., Piva A., Roth F.X. (2004). The effect of gluconic acid on growth and intestinal microflora of weanling pigs. FRANKFURT AM MAIN : DLG Verlag.
The effect of gluconic acid on growth and intestinal microflora of weanling pigs
BIAGI, GIACOMO;VEZZALI, ENRICO;PIVA, ANDREA;
2004
Abstract
The effect of gluconic acid on growth and intestinal microflora of weanling pigs (Einfluss von Gluconsäure auf Wachstum und intestinale Mikroflora von Absetzferkeln). G. Biagi*, E. Vezzali, A. Piva and F.X. Roth – Bologna/Freising-Weihenstephan The finding that antibiotics fed to farm animals as growth promoters can be responsible for the spreading of resistant bacteria and the consumer demands for a food chain free of drugs determine the need to study alternative strategies to control microbial activity in the gastrointestinal system of monogastric animals. Gluconic acid (GA) has been shown to reach the large intestine in rats where it can be fermented by the microflora (1). Aim of this study was the evaluation of the effect of feeding GA on piglet growth and intestinal microflora. Methods: Immediately after weaning, 48 piglets were divided into 4 groups (12 animals per group, housed in individual cages) for a 6 week trial. Treatments were a commercial diet with a) no addition (control diet) or with b) 0.3%, c) 0.6%, and d) 1.2% of GA. Feed and water were provided ad libitum. Animals were weighed every week and feed consumption was recorded. At day 10 and 31, faecal samples were collected from 6 animals per group and cultured for viable bacteria (coliforms, clostridia and lactobacilli). At the end of the trial, 4 animals per group were killed. Samples of jejunum and caecum content were cultured for viable bacteria and their ammonia and volatile fatty acids (VFA) content as well as pH were determined. Results: Feeding 0.3 and 0.6% of gluconic acid increased average daily gain (ADG) compared to control (P < 0,10), while gain to feed ratio (GF) was not influenced by treatments (Table 1). Faecal bacterial counts after 2 weeks did not show any differences. At week 5, coliforms were markedly reduced by the 0.3% GA treatment compared to control (P < 0.10) and all GA diets showed a tendential increase of the number of lactobacilli. In the caecum, clostridia were significantly reduced by GA at 0.6 and 1.2% (P < 0,10). As previously observed in the faeces, lactobacilli were tendentially increased in the caecum by GA. Ammonia concentration in the intestinal samples was not influenced by treatments. VFA in the intestine were increased by GA, but the differences observed did not reach the significance level due to the high variability. Interestingly, GA mainly increased acetic acid in the jejunum and butyric acid in the caecum. Table 1. Live weight, average daily gain (ADG), daily feed intake and feed to gain ratio (FG) of piglets in the 6 weeks after weaning. Values are means of 12 animals ± SD. Final live weight ADG Daily feed intake FG (kg) (g/d) (g/d) Control 25.08 ± 3,09 423 ± 67 704 ± 121 1.67 ± 0.06 Gluconic acid 0.3% 26.73 ± 2,73* 464 ± 55* 754 ± 108 1.62 ± 0.07 Gluconic acid 0.6% 26.85 ± 2,95* 466 ± 71* 749 ± 94 1.62 ± 0.08 Gluconic acid 1.2% 25.25 ± 2,22 428 ± 52 696 ± 68 1.63 ± 0.06 *Different from control by P < 0.10. Conclusion: The present results show how feeding GA can improve the growth performances of piglets after weaning. Nevertheless, when used at a high concentration (1.2 %) the positive effect of GA was not observed. The bacterial counts and the VFA analyses show that GA may influence the composition and the activity of the intestinal microflora. Further studies will be needed to achieve a better understanding of the mode of action of GA in pigs. 1) ASANO, T, YUASA, K, YOSHIMURA, Y, TAKENAWA, S and FUKUBA, H (1997): J. Jpn. Soc. Nutr. Food Sci. 50, 287-294. _______________________ *Department of Physiology and Animal Production, Faculty of Veterinary Medicine, University of Bologna, Via Tolara di Sopra 50, I-40064 Ozzano EmiliaI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
