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Abstract: An in vitro study was performed with the aim of describing the course of fermentation of pig liquid feed during incubation, including microbial characteristics and amino acid concentration in the mixture. A standard grower diet with added 2.0g lysine/kg, 2.0g methionine/kg, and 2.5g threonine/kg was formulated. Three experimental treatments were prepared: (1) the grower diet with added amino acids, ‘control’; (2) the grower diet with added amino acids +4.8g solid acidifier Boliflor® FA 2300S/kg liquid feed, ‘FA2300S’; (3) the grower diet with added amino acids +2.0g formic acid/kg liquid feed, ‘formic’. Feed and water were mixed in the ratio 1–2.75, and incubated in bioreactors with a volume of 1L at 20°C. The samples were incubated during 48h, during which no feed or water was removed or added. A sample was taken after 0, 6, 24, and 48h of incubation. After 48h of incubation, 90% of the mixture was removed and replaced with fresh feed and water, and the same procedure was followed at 55, 72, 79, and 96h of incubation. A sample was taken at 96, 102, and 108h of incubation. Enterobacteriaceae counts in the ‘control’ diet increased from time 0 to time 24h of incubation, and decreased at time 48h. The Enterobacteriaceae counts in the ‘FA2300S’ and ‘formic’ diets decreased with time of incubation during the first 48h to levels between <3.0 and 3.3logcfu/g sample. From 96 to 108h of incubation, the Enterobacteriaceae counts decreased in all three diets, being lowest in the ‘formic’ diet at all three sampling times and highest in the ‘control’ diet. The concentration of total and free lysine (g/kg crude protein), threonine, and methionine decreased with time of incubation in all diets. From 96 to 108h of incubation, ∼5 to 9% total lysine, ∼12 to 13% total threonine, and ∼17 to 19% total methionine had been degraded. During the same incubation time, ∼26–34% free lysine, ∼31–38% free threonine, and ∼31–42% free methionine had disappeared. Addition of 2.0gformicacid/kg pig liquid feed or 4.8g Boliflor® FA 2300S/kg pig liquid feed are strategies that impede the proliferation of Enterobacteriaceae during the first hours of fermentation but have no effect on amino acid degradation. A disappearance of, mainly, free amino acids occurs during fermentation of liquid feed as prepared in the present study. [Copyright &y& Elsevier]

Fluctuating prices on feedstock has led to a growing interest in alternative feed ingredients. Co-products from the biofuel industry are hence interesting to include in pig feeds, primarily due to the high protein content. Low nutritional value due to a high content of dietary fibre, however, limits the use of these ingredients. The current study aimed to increase the digestibility of dried distillers grains with solubles (DDGS), based on 80% wheat and 20% barley, by fermentation and enzyme addition. Four experimental diets were prepared based on 60% DDGS (fermented or not, without or with the addition of carbohydrases) and 40% of a basal diet composed mainly of maize starch: (1) a nonfermented liquid feed treatment (n-FLF); (2) a fermented liquid feed treatment (FLF); (3) the FLF supplemented with a mixture of xylanase and β-glucanase (XylGlu); and (4) the FLF supplemented with a mixture of cellulase and xylanase (CelXyl). Microbial population during fermentation of the treatments was determined and apparent ileal and total tract digestibility were measured on eight barrows surgically fitted with a simple T-shaped cannula at the distal ileum and fed the four treatments according to a double-Latin square design. Microbial activity of the three fermented DDGS treatments was relatively low with lactic acid bacteria counts between 8.8 and 8.9 log cfu/g and lactic acid concentrations between 60.2 and 70.5 mmol/kg. The addition of CelXyl to DDGS resulted in a significant decrease in the amount of non-starch polysaccharides (NSP) compared to the fermented DDGS (from 341.8 g/kg DM to 312.9 g/kg DM, P <0.001). Furthermore, addition of CelXyl to DDGS showed a reduction in the level of putrescine (46.5 mg/kg DM in the DDGS versus 3.7 mg/kg DM in the DDGS added CelXyl). Fermenting DDGS prior to feeding led to significantly increased apparent ileal digestibility (AID) of NSP ( P =0.02), and apparent total tract digestibility (ATTD) of DM ( P =0.01), CP ( P =0.003), and P ( P =0.04), along with tendency to increased ATTD of NSP ( P =0.1). Addition of XylGlu and CelXyl resulted in further increases of both AID and ATTD of NSP compared to n-FLF ( P ≤0.03); with the greatest effect on the CelXyl treatment. In conclusion, the digestibility of DDGS in pigs was increased by fermentation. Addition of carbohydrases during fermentation can be a way of further increasing the NSP digestibility of DDGS. [ABSTRACT FROM AUTHOR]

The objective of the present study was to evaluate the optimum ratio of standardized ileal digestible (SID) Trp to Lys for pigs after weaning. A total of 96 female pigs were allocated to 1 of 6 diets containing 0.13, 0.15, 0.17, 0.19, 0.21, and 0.23 SID Trp:Lys, with 16 individually housed pigs/treatment. The diets contained similar crude protein (154 g/kg), NE (10.5 MJ/kg), and SID Lys (10.9 g/kg). Average daily feed intake (ADFI), average daily gain (ADG), and gain to feed ratio (G:F) were determined for a 21-d period. Blood and urine samples were collected on d 8 and 15. Urea concentration in plasma and urine decreased ( P <0.001) concurrently with increasing SID Trp:Lys. The ADFI, ADG, and G:F improved ( P <0.001) with increasing SID Trp:Lys. By fitting by a curvilinear-plateau model, minimum SID Trp:Lys to support optimum ADFI, ADG, and G:F were estimated to be 0.20, 0.20, and 0.16, respectively. By fitting a broken-line model, the minimum SID Trp:Lys was estimated to be 0.18, 0.18, and 0.15 for optimum ADFI, ADG, and G:F, respectively. In conclusion, growth performance of pigs weighing 7–14 kg increased up to 0.20 SID Trp:Lys. [ABSTRACT FROM AUTHOR]