Effect of wet/dry, fresh liquid, fermented whole diet liquid and fermented cereal liquid feeding on feed microbial quality and growth in grow-finisher pigs.

: Fermented liquid feeding has proved beneficial for weaner pigs; however, there is limited research on its effect on the growth and feed conversion efficiency (FCE) of grow-finisher pigs. Microbial decarboxylation of amino acids is associated with whole diet fermentation, while wet/dry and liquid feeding reportedly improve growth compared to dry feeding. The objective of this study was to determine the effect of wet/dry feeding and fresh, fermented whole diet and fermented cereal liquid feeding on pig growth, feed efficiency and carcass quality in grow-finisher pigs. Pigs were allocated to one of four dietary treatments in two experiments: 1. Single-space wet/dry feeders (WET/DRY), 2. Fresh liquid feeding (FRESH), 3. Fermented cereal liquid feeding where the cereal fraction (38 % barley, 40 % wheat) of the diet was fermented prior to feeding (FERM-CER), 4. Fermented whole diet liquid feeding where the whole diet was fermented prior to feeding (FERM-WH). In Exp. 1, pigs were fed the experimental diets for 68 days prior to slaughter (29.8 kg ± 0.92 SE to 102.3kg ± 0.76 SE). Overall, average daily gain (ADG) was 1094, 1088, 1110 and 955 g/day (SE = 13.0; P < 0.001) and FCE was 2.26, 2.37, 2.40 and 2.88 (SE = 0.031; P < 0.001) for treatments 1 through 4, respectively. Pigs fed FERM-WH were lighter at slaughter than pigs fed the other three treatments (P < 0.001). In Exp. 2, pigs were on treatment for 26 days prior to slaughter (85.3kg ± 1.69 SE to 117.5kg ± 0.72 SE). Overall ADG in Exp. 2 was 1103, 1217, 1284 and 1140 g/day (SE = 27.9; P < 0.01) and FCE was 2.78, 2.99, 2.95 and 3.09 g/g (SE = 0.071; P = 0.05), for treatments 1 through 4, respectively. There were no significant differences observed between treatment for apparent total tract digestibility of dry matter, organic matter, nitrogen, gross energy or ash. Higher lactic acid bacteria counts and lower Enterobacteriaceae counts and pH were observed in FERM-CER and FERM-WH compared with WET/DRY and FRESH. Ethanol concentrations were almost four-fold higher in FERM-CER troughs than FRESH troughs and five-fold higher in FERM-WH than FRESH troughs. To conclude, whole diet fermented liquid feeding resulted in poorer growth and FCE compared with wet/dry, fresh liquid and fermented cereal liquid feeding, probably due to amino acid degradation and a loss in gross energy found in FERM-WH.