Synergistic effect of exogenous multi-enzyme and phytase on growth performance, nutrients digestibility, blood metabolites, intestinal microflora and morphology in broilers fed corn-wheat-soybean meal diets

Effect of a novel alkaline protease from Bacillus licheniformis on growth performance, carcass characteristics, meat quality, antioxidant capacity, and intestinal morphology of white feather broilers

BACKGROUND

The present study was conducted to investigate the effects of dietary novel alkaline protease from Bacillus licheniformis on the growth performance, meat quality, antioxidant status and intestinal morphology of broilers. In total, 4000 broilers were randomly assigned into five groups and treated with normal control, normal control + 100 mg kg-1 protease, normal control + 200 mg kg-1 protease, normal control + 300 mg kg-1 protease and normal control + 400 mg kg-1 protease.

RESULTS

Supplementing protease impacted final body weight (linear, P = 0.003; quadratic, P = 0.006) and decreased feed conversion rate (linear, P = 0.036) in broilers. Moreover, dietary protease significantly increased breast muscle rate (linear, P = 0.005; quadratic, P = 0.021) and decreased drip loss (linear, P < 0.001; quadratic, P < 0.001). In addition, dietary protease notably increased protein digestibility (linear, P = 0.001; quadratic, P = 0.006) and trypsin activity (linear, P = 0.002; quadratic, P = 0.009) in jejunum. Light microscopy revealed that the jejunum villi in the 300 mg kg-1 and 400 mg kg-1 groups exhibited greater height and a denser arrangement compared to those in the control group. The addition of protease decreased malondialdehyde content (linear, P < 0.001; quadratic, P < 0.001) and increased total antioxidant capacity (linear, P = 0.001; quadratic, P < 0.001) in pectoral muscles.

CONCLUSION

The results of the present study suggest that dietary novel alkaline protease from B. licheniformis improved growth performance by affecting trypsin activity, protein digestibility, antioxidant capacity and intestinal health. © 2024 Society of Chemical Industry.

Effect of an Escherichia coli-derived phytase and a carbohydrase-protease cocktail derived from Bacillus spp. on performance, digestibility, bone mineralization and gut morphology in broilers fed different nutrient density diets

BACKGROUND

Enzyme combinations, particularly phytase (PHY) with various carbohydrases and proteases, are utilized in commercial broiler production to enhance nutrient and energy bioavailability.

OBJECTIVE

A feeding study was undertaken to determine whether the efficiency of an Escherichia coli-derived PHY and a feed enzyme complex (FEC) derived from Bacillus spp. containing carbohydrase and protease as main activities in broiler chickens is dependent on diet quality. A total of 900 male one-day-old broiler chickens (Ross 308) were assigned to a 2 × 3 factorial arrangement of the treatments with 2 different nutrient density diets, standard nutrient diet (SN diet) and a low-nutrient diet (LN diet; -100 kcal/kg for AMEn and -5% for crude protein [CP] and limiting amino acids), and 3 enzyme treatments (control [no enzymes], PHY and PHY + FEC). Each treatment group was composed of 6 replicates of 25 birds each.

RESULTS

The LN diet caused a decrease in performance index, tibia length and diameter, tibia calcium content and jejunal villus surface area (VSA). The interaction effects between diet and enzyme supplementation were observed (p < 0.05) on overall average daily gain (ADG), performance index, tibia ash content and jejunal villus height (VH) and VSA, with the favourable benefits of PHY + FEC treatment being more pronounced in the LN diets. Regardless of dietary nutrient density, supplementation with PHY alone or combined with FEC enhanced (p < 0.05) final body weight, overall ADG and jejunal villus height (VH)/crypt depth, with the highest values observed in the PHY + FEC group. The PHY + FEC treatment also improved (p < 0.05) overall feed conversion ratio, apparent ileal digestibility of dry matter, organic matter, CP, and energy, and tibia phosphorus content compared to the control treatment.

CONCLUSIONS

The results indicate that the simultaneous addition of PHY and FEC to the LN diets improved the growth rate, bone mineralization and gut morphology.

Interactions between enzyme preparations and trace element sources on growth performance and intestinal health of broiler chicks

This experiment was conducted to explore the interactions between enzyme preparations and trace element sources on growth performance and intestinal health of broilers chicks. A total of 480 one-day-old healthy male yellow-feather broilers with similar weight were randomly arranged in a 2  ×  2 factorial design with 2 kinds of compound trace element sources (inorganic [I] and organic [O] trace element supplemented with 80, 8, 60, 40, 0.15 mg/kg of Fe, Cu, Mn, Zn, and Se, respectively) and 2 levels of enzyme preparations (0 and 200 mg/kg). The 4 groups named I, O, IE, and OE with 6 replicates and 20 birds per replicate. The trail lasted for 28 days. Results showed that the average weight (ABW), average daily gain (ADG) of broilers in IE and OE groups significantly increased while the F/G significantly decreased as compared with group I and O (P < 0.05). Enzyme preparation supplementation, regardless of the trace element sources, significantly increased the duodenal and jejunal endogenous enzyme (e.g., Try and AACT) activity, and improved the morphology and jejunal barrier function evidenced by the increased villus height and MUC-2 mRNA expression (P < 0.05). Sequencing data manifested that enzyme preparations favorably modulated the cecal microflora by increasing bacterial diversity and abundance of short-chain fatty acid (SCFA)-producing bacteria (e.g., Anaerostipes, Anaerofusis, and Pygmaioactor), while decreasing the abundance of harmful bacteria (e.g., Desulfovibrio). Factorial analysis indicated that there were no interactions between enzyme preparation and trace element sources on growth performance and intestinal health of broiler chicks. In conclusion, dietary supplementation with enzyme preparations, regardless of the trace element sources, could enhance endogenous enzyme activity, improve intestinal morphology and barrier functions, and favorably modulate the cecal microflora, thereby improving the intestinal health and growth performance of broiler chicks.

Effects of nonantibiotic growth promoter combinations on growth performance, nutrient utilization, digestive enzymes, intestinal morphology, and cecal microflora of broilers

Given the ban on antibiotic growth promoters, the effects of nonantibiotic alternative growth promoter combinations (NAGPCs) on the growth performance, nutrient utilization, digestive enzyme activity, intestinal morphology, and cecal microflora of broilers were evaluated. All birds were fed pellets of two basal diets-starter (0-21 d) and grower (22-42 d)-with either enramycin (ENR) or NAGPC supplemented. 1) control + ENR; 2) control diet (CON, basal diet); 3) control + mannose oligosaccharide (MOS) + mannanase (MAN) + sodium butyrate (SB) (MMS); 4) control + MOS + MAN + Bacillus subtilis (BS) (MMB); 5) control + MOS + fruit oligosaccharide (FOS) + SB (MFS); 6) control + FOS + BS (MFB); 7) control + MOS + FOS + MAN (MFM); 8) control + MOS + BS + phytase (PT) (MBP). ENR, MOS, FOS, SB, MAN, PT, and BS were added at 100, 2,000, 9,000, 1,500, 300, 37, and 500 mg/kg, respectively. The experiment used a completely random block design with six replicates per group: 2400 Ross 308 broilers in the starter phase and 768 in the grower phase. All NAGPCs significantly improved body weight gain (P < 0.01), utilization of dry matter, organic matter, and crude protein (P < 0.05), villus height and villus height/crypt depth in the jejunum and ileum (P < 0.01), and decreased the feed conversion ratio (P < 0.01) at d 21 and 42. MMS, MMB, MFB, and MFM duodenum trypsin, lipase, and amylase activities increased significantly (P < 0.05) at d 21 and 42. On d 21 and 42, MMS, MMB, and MBP increased the abundance of Firmicutes and Bacteroides whereas MMB, MFB, and MBP decreased the abundance of Proteobacteria, compared to ENR and CON. Overall, the NAGPCs were found to have some beneficial effects and may be used as effective antibiotic replacements in broilers.