Effect of exogenous fibrolytic enzymes on ruminal fermentation and nutrient digestion in dairy cows.

The aim of the present study was to examine the effects of an exogenous fibrolytic enzyme product applied to a total mixed ration (TMR) prior to feeding on ruminal fermentation, microbial protein synthesis, nutrient digestion, and milk yield and composition. Six multiparous lactating Holstein cows (598 +/- 29 kg initial live weight and 98 +/- 30 days in milk) fitted with rumen and duodenal cannulae were allocated to two treatments in a crossover design over three consecutive 28-d periods. The TMR containing 50% concentrates, 30% corn silage and 20% grass silage on dry matter (DM) basis, was mixed once daily and fed twice a day. Treatments were TMR alone (Control) or TMR with an enzyme product containing primarily cellulase and xylanase activities (9000 U endo-1,4-beta glucanase, 24000 U endo-1,3(4)-beta glucanase and 40000 U 1,4-beta xylanase per ml). The enzyme product was applied at a rate of 6.2 ml/kg TMR (DM basis). It was diluted at a rate of 1:5 with water and applied daily to the TMR. During the control period the cows received a TMR supplemented with 36 ml water/kg TMR on DM basis. Duodenal digesta flow was measured using Cr2O3 as flow marker and microbial protein in the duodenal digesta was estimated by near-infrared spectroscopy (NIRS). There were no significant differences in ruminal pH-values, NH3-N concentrations, total SCFA concentrations and molar proportions of SCFA. No treatment effects on microbial N flow to the duodenum and efficiency of microbial protein synthesis were observed. The apparent ruminal digestibilities of DM, organic matter, NDF and ADF, milk yield and composition were also not affected by the enzyme supplementation. In this study the application of exogenous fibrolytic enzymes fed to dairy cows did not show a significant effect on any parameter tested.

Enzyme complex containing carbohydrases and phytase improves growth performance and bone mineralization of broilers fed reduced nutrient corn-soybean-based diets.

One experiment was conducted to investigate the benefits of a multi-enzyme complex, containing carbohydrases (from Penicillium funiculosum) and phytase (bacterial 6-phytase) activities, on the performance and bone mineralization of broiler chickens fed corn-soybean meal diets. A total of 2,268 male broilers were allocated to 9 treatments, replicated 6 times, in a randomized complete block design from 1 to 43 d. A positive control (PC) diet formulated to be adequate in nutrients and 4 reduced nutrient diets (NC1 to NC4), with gradual decrease on AME, CP, and digestible amino acids (CP-dAA) and available P (avP) and Ca contents, with or without enzyme supplementation, were tested. The nutrient reductions applied were NC1 (-65 kcal/kg, -1.5% CP-dAA) and NC2 (-85 kcal/kg, -3.0% CP-dAA) both with -0.15 percent point avP and -0.12 percent point Ca and NC3 (-65 kcal/kg, -1.5% CP-dAA) and NC4 (-85 kcal/kg, -3.0% CP-dAA) both with -0.20 percent point avP and -0.16 percent point Ca. Supplementation of the NC diets with the enzyme complex increased ADFI (P<0.001), ADG (P<0.001), and reduced feed:gain (P<0.01). The magnitude of the enzyme effect in increasing feed intake and weight gain was greater for the diets with greatest reductions in avP and Ca. Enzyme supplementation increased (P<0.001) feed intake of birds fed on NC diets close to the level of feed consumption of the PC. Enzyme supplementation to NC diets resulted in all cases in lower (P<0.05) feed:gain than the PC. Enzyme supplementation to NC1 and NC3 diets restored bone mineralization to that of the PC, whereas ash and Ca with NC2 and NC4 diets and P with NC4 diet remained lower (P<0.05). These results suggest that the dietary supplementation with a multi-enzyme complex containing nonstarch polysaccharide enzymes and phytase is efficient in reducing the P, energy, protein, and amino acid specifications of corn-soybean meal diets.

Influence of enzyme supplementation and heat processing of barley on digestive traits and productive performance of broilers.

We studied the influence of enzyme supplementation (ES) of the diet and heat processing (HP) of barley on digestive traits and productive performance of broilers from 1 to 42 d of age. There were 6 diets arranged factorially with 2 doses (0 and 500 ppm) of a fungal enzyme complex with beta-glucanase and xylanase activity and 3 HP of barley (raw, micronized, and expanded). In addition, a control diet based on raw corn without ES was also included from 1 to 21 d of age. Enzymes reduced intestinal viscosity (IV) at all ages (P < or = 0.001) and water intake at 21 d of age (P < or = 0.01) and increased DM of the ileal contents at 28 d (P < or = 0.001). Also, ES increased total tract apparent retention of nutrients and BW gain and feed conversion ratio from 1 to 42 d of age (P < or = 0.001). Heat processing of barley increased IV at 7 and at 28 d of age, and DM of ileal contents (P < or = 0.05) at 28 d of age. In addition, HP improved feed intake (P < or = 0.01) and BW gain (P < or = 0.001) from 1 to 7 d of age, but the effects disappeared after 21 d of age. From 1 to 7 d of age, chicks fed micronized barley had higher IV, gained less weight, and had poorer feed conversion ratio than chicks fed expanded barley (P < or = 0.05). It is concluded that barley with enzymes can substitute for all of the corn in diets fed to broilers from 1 to 21 d of age. Enzymes improved digestive traits, retention of nutrients, and broiler performance from 1 to 42 d of age, and HP of barley improved performance from 1 to 7 d of age. The effects of HP of barley on broiler performance were more evident with expansion than with micronization.

Effects of dietary fat type and non-starch-polysaccharide-hydrolysing enzyme addition to rye-based diets on muscle protein turnover in broilers.

1. Muscle protein turnover was measured in broilers fed on rye-based diets containing either beef tallow (T) or soybean oil (S) at an inclusion rate of 100 g/kg. Each of these diet types was tested either in the absence (S[-], T[-]) or presence (S[+], T[+]) of a xylanase-containing enzyme preparation. Protein turnover was measured in gastrocnemius muscle (GM) and pectoralis major muscle (PM). 2. Fractional rate of protein synthesis (FSR) was measured by the large dose technique using [15N]-labelled phenylalanine whereas fractional protein growth rate (FGR) was estimated by regressing tissue protein content over time. Fractional breakdown rates (FBR) were calculated by the difference between FSR and FGR. 3. In PM, FSR (%/d) was 22.1, 23.4, 21.5 and 24.4 in groups S[-], S[+], T[-] and T[+], respectively, and FBR (%/d) was 8.3, 9.8, 4.5 and 10.8 with the xylanase effect being significant. The FGR of 17.0%/d calculated for the broilers fed on the T[-] diet tended to be higher than for the other groups (13.6 to 13.8%/d). No significant effects were detected for these parameters in the GM. 4. The absolute amounts of protein which were synthesised daily and accreted in both muscles were significantly higher with xylanase supplementation in both fat type diets but at a significantly higher level when soybean oil was the dietary fat type. 5. The observed effects on protein turnover have to be seen in the context of an overall adverse effect of dietary soluble pentosans from rye in combination with tallow on physico-chemical chyme conditions, digestion and absorption of energy and nutrients and tissue-specific metabolic changes.