Potato (Solanum tuberosum L. cv. Gogu valley) protein as a novel antimicrobial agent in weanling pigs

¹ Division of Animal Resources Science, Kangwon National University, Chuncheon
² School of Veterinary Medicine, Kangwon National University, Chuncheon
³ School of Biotechnology, Kangwon National University, Chuncheon
⁴ Research Centre for Proteineous Materials, Chosun University, Kwangju, Republic of Korea
⁵ Dept. of Animal Product and Food Science, Kangwon National University, Chuncheon

^* To whom correspondence should be addressed. E-mail: bjchae{at}kangwon.ac.kr.

	Abstract

A total of 280 weaned pigs (Landrace x Yorkshire x Duroc) were used in a 28 d growth study to investigate the effect of feeding different levels of potato (Solanum tuberosum L. cv. Gogu valley) proteins on growth performance, nutrient digestibility, immune response, small intestinal morphology, and bacterial populations in feces and large intestine. Pigs (initially 6.42 ± 0.74 kg BW and 23 ± 3 d of age) were randomly allotted to 5 treatments on the basis of BW, each treatment comprised of 4 pens and each pen had 14 pigs. Dietary treatments included: PC (positive control; basal diet + 150 ppm apramycin and 10 ppm colistin sulfate); PP (potato protein) basal diet with 0, 0.25, 0.50 or 0.75% of potato protein). Diets were fed in two phases: phase I (d 0 to 14) and phase 2 (d 14 to 28). Potato protein was extracted from value-added type of the new potato variety (Solanum tuberosum L. cv. Gogu valley) and was shown to have a minimum inhibitory concentration of 300 to 500 µg/mL. Performance of PC was compared with 0.25 to 0.75 % PP, while linear and quadratic trends of increasing PP (0 to 0.75% PP) were tested. Over the 28-d trial, pigs fed PC diets showed improved overall ADG (P < 0.05) and G:F (P = 0.090) compared to pigs fed PP; whereas, increasing levels of PP linearly improved ADG (P < 0.05), ADFI (P = 0.052) and G:F (P = 0.098). The digestibility of DM and CP in both the phases was higher in PC than PP, and feeding of PP linearly improved the DM digestibility (P < 0.05) in phase II. The bacterial populations in the feces of pigs fed PC and PP were comparable, except for total bacteria and coliform bacteria in the feces at d 14 and 28 that were decreased in PC; and feeding of PP was effective in linearly reducing the populations of microbes in feces and contents of caecum, colon and rectum. There was linear increase (P < 0.10) in skin-fold thickness in response to phytohemagglutinin with an increase in PP levels. Haemagglutinin (HA) titers on d 21, were greater (P = 0.054) in PC, and at d 28, HA titers were quadratically affected in pigs fed PP (P = 0.070). There was a trend towards decrease in crypt depth (P = 0.068) and higher villus height:crypt depth ratio (P = 0.082) of ileum in PC when compared with PP. These results suggest that PP may be an alternative to medicated feed with antibiotics because it showed antimicrobial activity by effectively reducing the population of coliform bacteria and also improved the performance of weanling pigs.

Key Words: antimicrobial activity, growth performance, intestinal morphology, nutrient digestibility, potato protein, weanling pigs