Effect of probiotic and lactoferrin-supplemented diets on daily gain, feed intake, feed conversion rate, mean weekly faecal scores, lymphcyte to neutrophil ratio, immunity, general health, and hematological parameters in weanling pigs subjected to an immunological challenge : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science (Animal Science) at Massey University, Palmerston North, New Zealand

Abstract

Background The digestive system of early weaned pigs is not fully developed and animals can be subjected to a post-weaning check, or lag period, which results in poor feed intake, weight gain, immunity and high diarrhoea cases and mortality. In addition, there is a depression of growth during an immune challenge that results in nutrient intake restriction and redirection to support the immune system. A shift from the unstable flora at weaning into a complex stable one would be achieved by diet manipulation. Different natural products (instead of hazardous antibiotics) are being tested to find their ability in improving pig health and performance. The aim of this study was therefore to evaluate the effects of dietary supplementation with probiotics and lactoferrin on pigs' growth performance, haematological characteristics and general health. The weaned pigs from four different farms were mixed together upon arrival to place them in an immune challenging environment. Results After 21 days post challenge/weaning, average daily feed intake, ADFI (404.64, 426.77, 423.63, 378.48 and 341.48 g/p/d for diet for diet A[control], B, C, D (probiotics) and E [lactoferrin], respectively) was significantly different in pigs that consumed the five diets (p=0.0259). Pigs that consumed diet B had 5.47% higher feed intake (p<0.05) than the controls, while those that received diet C consumed 4.69% more feed than the controls but this feed intake was not significantly different from that of the controls (p>0.05). The difference in feed intake between pigs in fed diet B and C was also not significant (p>0.05). Animals that were allocated to diet D and diet E (lactoferrin) consumed significantly less feed compared to the controls (p<0.05). Feed consumption was 6.47% and 15.61% lower (p<0.05) for pigs fed diet D and E, respectively, compared to the controls. Pigs that received diet D consumed significantly higher amounts of feed (p<0.05) than those fed diet E (lactoferrin). In conclusion, in the first three weeks of life, or at times of stress such as weaning and / or immune challenge, a good probiotic (such as B or C) should produce a faster and more rapid response by increasing / stimulating feed intake so that body weight losses are quickly compensated. Feed intake is a factor that limit growth in weaned piglets. Weight is gained after the improvement in feed ingestion. Reduction in feed / energy intake also reduces body weight. If feed (energy) intake is reduced, then, a good diet should stimulate quick repair of the gut and improve intestinal environment architecture and integrity. When feed consumption increases, the levels of digestive enzymes responsible for the breakdown of fats, starches and proteins increase. When feed intake is not increased or increased too late after weaning, bodyweight may not be compensated.