Comparative effects of two multi-enzyme combinations and a Bacillus probiotic on growth performance, digestibility of energy and nutrients, disappearance of non-starch polysaccharides, and gut microflora in broiler chickens

The efficacy of two exogenous enzyme combinations and a multi-strain Bacillus probiotic (DFM) on the growth performance, nutrient digestibility, disappearance of non-starch polysaccharides (NSP) and gut microbial composition was investigated in broilers. One-day old Ross 308 chicks were assigned to 36 pens with 22 birds/pen and 6 pens/treatment (Experiment 1) or 36 cages with 8 birds/cage and 6 cages/treatment (Experiment 2). Treatment additives were added to nutritionally complete corn/soy based starter (d 1 to 21) and finisher (d 22 to 42) diets. Treatments included 1) a control diet containing 500 FTU/kg phytase (CTL), 2) CTL + xylanase (2,000 U/kg) and amylase (200 U/kg; XA), 3) CTL+XA + protease (4000 U/g; XAP), 4) CTL+DFM (150,000 cfu/g of 3 strains of Bacillus spp), 5) CTL+DFM+XA, and 6) CTL+DFM+XAP. Supplementation with DFM increased BW, BWG, and FI compared with the CTL (P < 0.05); XAP, but not XA, resulted in increased final BW, BWG and FI compared to the control (P < 0.05). XA and XAP improved apparent ileal digestibility (AID) of starch and fat on d 22 to 42 with XAP improving AME_n (by ∼82 kcal) compared with CTL birds (P < 0.01). DFM+XAP improved apparent ileal digestible energy (AIDE), AID of fat and starch on d 22 to 42, and additionally had a greater than additive effect on AIDE and AME_n. Supplementation with DFM+XAP reduced the ileal and total tract flow of insoluble arabinose and additionally total tract flow of soluble and insoluble xylose and total galactose (P < 0.05); similar effects of XA+DFM were not seen or were lower in magnitude, suggesting that the protease component plays an important role in increasing the availability of NSP for hydrolysis. Supplementation with DFM alone did not affect gut bacterial populations, but XA and XAP reduced numbers of Campylobacter species (by > 2.5 log cfu/g; P < 0.001) and Bacteroides (P < 0.02) in the cecum compared with CTL birds.

Energy and nutrient utilization of broiler chickens fed corn-soybean meal and corn-based diets supplemented with xylanase

A study was conducted to evaluate the effects of increased levels of a β-xylanase on energy and nutrient utilization of broiler chickens fed corn-soy diets. A total of 480 slow feathering Cobb × Cobb 500 male broilers were randomly distributed to 10 treatments having 8 replicates of 6 birds each. Birds were fed a common starter diet to d 14 post hatch (3,050 kcal/kg AMEn, 21.7% CP, 1.05% Ca, and 0.53% nPP). The experimental diets were provided afterwards until 25 d. Two experimental diets, a conventional corn/soy-based basal diet (CS) and the basal diet in which 40% of the diet was displaced by corn (CN), were fed as-is or supplemented with 50, 100, 150, or 200 fungal β-xylanase units (FXU)/kg. Dietary treatments were distributed factorially as a 2 × 5 arrangement. Samples of feed, excreta, and ileal digesta were analyzed for determination of ileal digestible energy (IDE), metabolizable energy, and total tract retention of protein and lipid. No interactions between diet and xylanase were observed. The CS diets had higher (P < 0.05) energy utilization and nutrient digestibility when compared to the CN diets. AMEn and IDE were improved (P < 0.05) by 192 and 145 kcal/kg, respectively, when diets were supplemented with 100 FXU/kg xylanase. The xylanase added to the CN diet led to quadratic increases (P < 0.05) in IDE (Y = - 0.014x(2) + 2.570x + 3,155; r(2) = 0.60) and in AMEn (Y = - 0.016x(2) + 3.982x + 3,155; r(2) = 0.68). Crude protein digestibility and AMEn were linearly increased (P < 0.05) when xylanase was added to the CN diet. In conclusion, energy utilization and digestibility of crude protein and dry matter increased with xylanase supplementation in corn/soy-based diets. When xylanase was tested in the CS diet, 92 and 124 FXU/kg maximized the energy release effect; however, the maximum energy response in the CN diet or corn was not achieved until 200 FXU/kg.

Contribution of protein, starch, and fat to the apparent ileal digestible energy of corn- and wheat-based broiler diets in response to exogenous xylanase and amylase without or with protease

The ileal energy contribution of protein, starch, and fat in response to 2 exogenous enzyme combinations was studied in 2 digestibility assays with 21- (experiment 1; 432 birds) and 42-d-old (experiment 2; 288 birds) Ross 308 broiler chickens. A 2 × 2 × 3 factorial arrangement of treatments with 2 base grains (corn or wheat), without or with high fiber ingredients (corn distillers dried grains with solubles and canola meal), and 3 enzyme treatments was implemented. Enzyme treatments, fed from 12 to 21 d or 32 to 42 d, were 1) without enzymes, 2) with xylanase from Trichoderma ressei (2,000 U/kg) and amylase from Bacillus licheniformis (200 U/kg; XA), or 3) with XA plus protease from Bacillus subtilis (4,000 U/kg; XAP). All diets contained Escherichia coli phytase (500 FTU/kg). Apparent ileal digestibility (AID) of protein, starch, and fat, as well as the apparent ileal digestible energy, were determined using titanium dioxide as inert marker. A generalized mixed model was used to test main effects and 2-way interactions at P < 0.05. An enzyme × grain interaction was detected for AID of starch at 21 and 42 d, and AID of fat at 21 d, with greater effects of enzymes in wheat-based compared with corn-based diets, but significant increments due to enzymes compared with controls in both diet types. Apparent ileal digestibility of fat at 42 d increased with enzyme supplementation compared with the control treatments. The XA and XAP treatments gradually (P < 0.05) increased AID of protein at 21 d, but only XAP increased AID of protein compared with the control at 42 d. Compared with the controls, XA increased AID energy by 52 or 87 kcal, and XAP by 104 or 152 kcal/kg of DM at 21 or 42 d, respectively. The caloric contribution of starch, fat, and protein were affected differentially by base grain and the presence of fibrous ingredients at 21 and 42 d of age.

Nitrogen and energy balance in growing mink (Mustela vison) fed different levels of bacterial protein meal produced with natural gas

The objective of this study was to estimate the effect of increasing the dietary content of bacterial protein meal (BPM) on energy and protein metabolism in growing mink kits. Sixteen male mink kits of the standard brown genotype were randomly fed one of four diets: A control (Diet I) based on high-quality fish meal, and three experimental diets in which 20% (Diet II), 40% (Diet III) and 60% (Diet IV) of the digested nitrogen (DN) was replaced with BPM. Nitrogen balance and respiration experiments (indirect calorimetry) were carried out when the animals were approximately 9.5, 14.5, 17.5, 23.5 and 28.5 weeks of age. The apparent digestibility of crude protein and energy decreased significantly with increasing dietary BPM. The retained nitrogen was 0.45, 0.54, 0.52 and 0.40 g/kg0.75 on Diets I, II, III and IV, respectively, the observed differences between diets being non-significant (p = 0.06). Heat production (HE) was between 645 and 665 kJ/kg0.75 on all diets (p = 0.78). Retained energy (RE) was approximately 150-160 kJ/kg0.75 on Diets I to III, whereas it was -11 kJ/kg0.75 on Diet IV, the differences being significant (p< 0.001). A lower feed intake and apparent digestibility of energy caused the negative RE on Diet IV. The amount of HE from oxidation of protein decreased from 32.7% on Diet I to 26.6% on Diet IV, and oxidation of fat increased from 53.8% on Diet I to 63.5% Diet IV. In conclusion, protein and energy metabolism remained unaffected when up to 40% of DN was derived from BPM.

Energy metabolism and nutrient oxidation in young pigs and rats during feeding, starvation and re-feeding

The investigation included individual measurements of energy metabolism and oxidation of nutrients in 12 castrated male pigs (Sus scrofa) (20-40 kg) and 12 male rats (Rattus norvegicus) (65-105 g). Measurements were carried out in 5-6 days balance periods with ad libitum feeding, followed by 3-4 days of starvation and 4 days of re-feeding. O2 consumption and CO2 production were measured by open-air-circuit respiration units. In the feeding period, protein retention in relation to metabolic live mass (kg(0.75)) was identical for pigs and rats, while there was a tendency of a higher fat retention in pigs than in rats. A substantial part of digested carbohydrate was not oxidized, but transferred to fat metabolism without significant differences (P > 0.05) between pigs and rats (18% vs. 22%). During starvation, nitrogen excretion in urine decreased to 226 mg/kg(0.75) in pigs and to 429 mg/kg(0.75) in rats, indicating a lower rate of body protein degradation in pigs. Heat production was reduced to 592 and 338 kJ/kg(0.75), while the contribution of heat from oxidation of protein (OXP), carbohydrate (OXCHO) and fat (OXF) showed the same pattern for pigs and rats during all periods. Heat production during feeding and re-feeding was covered by OXP+OXCHO with no OXF and reversibly after 2 days of starvation by OXP+OXF with no OXCHO. The rat may be a suitable model for pigs regarding general patterns of quantitative nutrient partition, but any direct application of results measured with rats to pigs shall be taken cautiously, keeping in mind that modern pigs have been selected for a high growth rate and protein deposition which has not been the case for the laboratory rat.