Alastair Campbell

Performance, Water Use and Effluent Output of Weaner Pigs Fed ad libitumwith Either Dry Pellets or Liquid Feed and the Role of Microbial Activity in the Liquid Feed

Forty eight and ninety six pigs weaned at 22.6 ± 2.6 days, were allocated to two trials to study the effect of feeding post-weaning diets ad libitum, either as dry pellets (DF) or as meal mixed with water in the ratio 2.5 :1 (LF). The trials, lasting 28 days, differed only in the type of trough used to present the liquid feed to the pigs. In both trials the daily gain of LF pigs over the 4 weeks of the trial was significantly (P < 0.001) better than that of the DF pigs. Daily gains for the two treatment groups were respectively 428 and 343 ± 15 g day -1 in Trial 1 and 454 and 397 ± 10 g day -1 in Trial 2. The feed conversion ratio (FCR) (corrected to fresh weight of dry feed) of LF pigs was significantly poorer (P<0.01) than that of DF pigs in both trials primarily as a result of feed wastage by the LF pigs. FCR for the DF and LF pigs was, respectively, 1.31 and 1.89 ± 0.05 in Trial 1. In Trial 2 improvements in the trough design reduced the difference in FCR. FCR for the DF and LF treatments was 1.37 and 1.44 ± 0.02 respectively. In Trials 1 and 2 LF pigs used on average 76% and 35% more water than DF pigs. LF pig produced 12% (Trial 1) and 5.7% (Trial 2) more effluent per unit of liveweight gain than DF pigs. Microbiological examination of the liquid feed system demonstrated that the system acted as a fermenter. Lactobacillus spp proliferated rapidly and became the dominant organism within 5 days and the populations remained relatively constant thereafter. The proliferation of lactobacilli reduced the pH of the liquid feed from approximately 6.0 to between 3.5 and 4.0. At the lower levels of pH the number of coliforms in the feed was significantly reduced.

The effect of fermented liquid feeding on the faecal microbiology and colostrum quality of farrowing sows

This study investigated the effects of fermented liquid feed (FLF) on the lactic acid bacteria (LAB):Coliform (L:C) ratio in the faeces of farrowing sows and the quality of sow colostrum. Eighteen multiparous sows were randomly allocated to one of three dietary treatments for approximately 2 weeks prior to farrowing and for 3 weeks after parturition. The three dietary treatments were dry pelleted feed (DPF), nonfermented liquid feed (NFLF), and fermented liquid feed (FLF). A rifampicin-resistant mutant of Lactobacillus plantarum was used to ferment liquid feed. Coliforms and lactic acid bacteria (LAB) in the faeces of farrowing sows and piglets were estimated by standard microbiological techniques. Intestinal epithelial cells (IEC-6) and blood lymphocytes were used to evaluate the mitogenic activity of colostral samples taken at parturition. Results demonstrated that while the LAB population was not significantly affected by dietary treatment, significant differences in coliform population were observed in the sow faecal samples taken 7 days after parturition. Faeces excreted from sows fed FLF had significantly (P < 0.001) lower numbers of coliforms than sows fed NFLF or DF. Piglets from sows fed FLF excreted faeces that were higher in LAB (7.7 vs. 7.3 log10 CFU g (-1); P < 0.01) and lower in coliforms (7.5 vs. 8.1 log10 CFU g (-1); P < 0.001) than faeces from the piglets of DF-fed dams. Colostrum from sows fed FLF had a significantly greater (P < 0.001) mitogenic activity on both intestinal cells (IEC-6) (79326 +/- 3069 CPM) and blood lymphocytes (1903 +/- 204 CPM) compared with colostrum from dry feed fed sows (53433 +/- 1568 and 1231 +/- 61.4 CPM, respectively). The combined effects of enhanced maternal/passive immunity and the reduction in the level of environmental contamination with faecal pathogens, achieved by FLF, may be important in achieving improved health status for both sows and piglets.

Performance of Weaner Pigs Fed ad libitumwith Liquid Feed at Different Dry Matter Concentrations

The effect of feeding pigs weaned at 24 ± 2.6 days, ad libitum, a diet mixed with water to provide four different dry matter concentrations of 149, 179, 224 and 255 g kg -1 (diets DM149, DM179, DM224, DM255, respectively) was investigated in a 28 day feeding trial, utilising a total of 96 pigs. The diets were delivered by an automated system, the storage and mixing vessel of which was replenished daily. In addition to the water supplied in the liquid diet water was freely available to the pigs at all times from nipple waterers. Dietary dry matter (DM) concentration had no significant effect on DM intake, weight gain or DM feed conversion ratio of the piglets. Decreasing feed DM had a noticeable effect on total volumetric (DM plus water) intake of the piglets. When feed dry matter was reduced from 255 to 224 g kg -1 piglets reduced their voluntary water intake from nipple waterers in order to maintain DM intake and total volumetric intake. At lower DM concentrations, the pigs maintained DM intake by increasing their total volumetric intake. Piglets continued to consume an average of 223 ml water per day from the nipple waterers even at the lowest DM concentration. On DM149 total volumetric intake was 30% of live weight. The effect of dry matter (DM) concentration of feed on the pattern of microbial activity of the liquid feed system was investigated. Liquid diets were colonised rapidly by naturally occurring Lactobacillus spp in the first 5 days. After 5 days the population stabilised and remained constant for the remainder of the trial period. DM concentration of liquid feed had little overall effect on the pattern of microbial activity. The proliferation of Lactobacillus spp resulted in acidification of the liquid feed, (pH range 4.1-4.2) for all four treatments and this was associated with a lowering of coliform numbers. There was a significant increase in the overall effluent output as the DM content of the diet decreased (P < 0.01). It is concluded that weanling piglets will readily accept liquid feed with DM content in the range 255 to 149 g kg -1 , and that DM content in this range has little effect on post weaning performance. However, in order to maintain DM intake without increasing effluent output, it is recommended that the DM content of liquid diets should not be reduced below 200 g kg -1 (equivalent to a 3.5 :1 water to feed ratio).

Effect on weaner pig performance and diet microbiology of feeding a liquid diet acidified to pH 4 with either lactic acid or through fermentation with Pediococcus acidilactici

The effect of feeding newly weaned pigs acidified liquid diets was investigated. The control diet was acidified to about pH 4 with lactic acid (LA). A second diet of the same formulation was acidified to about pH 4 by fermentation with Pediococcus acidilactici (PA). Forty-eight weaner pigs (weight 7 kg±1 kg, age 24±4 days) were allocated to the two dietary treatments according to a randomised block design and fed ad libitum for 28 days. Food intake, daily gain and water intake were recorded, and a microbial assessment of the liquid diet was conducted. Reducing pH<4.0 in either of the liquid diets was effective in eliminating coliform bacteria. There were no significant differences in any of the performance parameters measured. The average daily liveweight gain overall was 474 and 496±17.8 g d−1 for PA and LA, respectively, with a feed conversion ratio overall of 1.15 and 1.11±0.025 for PA and LA, respectively. Fermentation of liquid diets for newly weaned piglets could provide a more cost effective means of acidifying diets than the use of organic acids. Reducing the pH of the liquid diet to 4.00 by fermentation with Pediococcus acidilactici was a cost effective method of eliminating enteropathogens and spoilage organisms from the diet. © 1999 Society of Chemical Industry

The effect of temperature on the growth and persistence of Salmonella in fermented liquid pig feed

Two studies were conducted to investigate the effect of temperature on the fate of Salmonella enterica subsp. enterica serovar typhimurium DT104:30 in fermented liquid pig feed. These were (1) by co-inoculation of feed with S. typhimurium DT104:30 and Pediococcus pentosaceus, as the fermenting organism, and (2) by fermenting feed for 48, 72 or 96 h prior to inoculation with S. typhimurium DT104:30. In co-inoculated feed incubated at 20 degrees C, S. typhimurium DT104:30 persisted for at least 72 h. In contrast, in feed incubated at 30 degrees C, no S. typhimurium DT104:30 were detectable 48 h after inoculation. In prefermented feed, S. typhimurium DT104:30 died four to five times faster in feed maintained at 30 degrees C (D(value) 34-45 min) compared with feed maintained at 20 degrees C (D(value) 137-250 min). This was not entirely due to differences in lactic acid concentration as feed fermented for 72 or 96 h at 20 degrees C and feed fermented for 48 h at 30 degrees C contained similar concentrations of lactic acid (160-170 mM). Low numbers of S. typhimurium DT104:30 were still detectable in fermented feed 24 h after inoculation at 20 degrees C. In contrast, none were detectable 6-7 h after inoculation at 30 degrees C. The results of these studies indicate that it would be advisable for pig producers to control the temperature of liquid feed tanks to reduce the risk of Salmonella contamination.

The effect of copper on the death rate of Salmonella typhimurium DT104:30 in food substrates acidified with organic acids

Aims:  The objective of this study was to investigate the effect of copper ions on the survival of Salmonella typhimurium DT104:30 in acidified liquid food substrates.