Quantification of supplemental enzymes in animal feedingstuffs by radial enzyme diffusion

Determination of the optimal priming interval of rumen fluids used as inocula for the in vitro digestibility trials through radial enzyme diffusion method

Context Determination of the neutral detergent fibre digestibility is one of the important parameters to consider when formulating diets. However, the in vitro determination shows low repeatability because of the source of rumen-fluid inoculum. Priming of the rumen fluid inocula, obtained through an oesophageal probe, has been proposed to overcome this issue. Aim The objective of the study was to investigate the evolution of the microbial enzymatic activities of different rumen fluids during a priming procedure, to establish the fermentation interval that minimises the differences among rumen-fluid degradative potentials. Methods Three farms for each type of diet were involved in the study. Rumen fluids were obtained from dry and lactating cows fed the following four diet types: 100% hay or a diet with 80:20 forage:concentrate ratio (F:C) as dry-cow diets, and ad libitum hay and concentrate, or a total mixed ration (both at 60:40 F:C) as lactating-cow diets. On each farm, rumen fluid was collected from three Holstein cows by using an oesophageal probe, and mixed. Two aliquots of each rumen fluid mix were added to the medium containing the same priming substrate in an in vitro batch-fermentation system. During the incubation, the fermentation fluids were sampled in duplicate at 0-, 1-, 2-, 4-, 8-, 24- and 48-h intervals. Enzymatic activities of amylase, cellulase and xylanase were determined by radial enzyme diffusion method. Key results Initial enzymatic activities were quite variable and increased with an increasing incubation time. By 24 h, amylase showed similar values among high-concentrate diet fermentation fluids, and a lower data dispersion in comparison to the other intervals; cellulase was characterised by similar values in all the fermentation fluids derived from diets including concentrates, and xylanase showed similar activity in the fermentation fluids derived from high-concentrate diets. Development of the enzymatic activity of the fermentation fluids derived from the 100% hay diet differed from the others. Conclusions A 24-h priming procedure was needed to stabilise and equalise the enzymatic activity of the rumen fluid from cows fed high-concentrate diets. This was not observed in rumen fluid from cows fed hay-based diets. Implications The 24-h-primed rumen fluid can be used to increase the repeatability of neutral detergent fibre digestibility determination.

Administration of Bacillus Amyloliquefaciens and Saccharomyces Cerevisiae as Direct-Fed Microbials Improves Intestinal Microflora and Morphology in Broiler Chickens

This study was conducted to investigate the effects of Bacillus amyloliquefaciens (BA) and Saccharomyces cerevisiae (SC) as directed-fed microbials on performance, intestinal microflora, and intestinal morphology in broiler chickens. A total of four hundred one-day-old broiler chickens were randomly divided into 16 pens of 25 chickens each, and every treatment had 4 replicated pens with two pens of males and females respectively. A formulated corn-soybean meal based control diets and experimental diets, including 0.1% BA (1×10⁷ colony-forming units (CFU)/kg), the mixture of 0.05% BA (5×10⁶ CFU/kg) and 0.05% SC (5×10⁶ CFU/kg), and 10 ppm antibiotic (avilamycin), were fed for 5 weeks. The results showed no significant difference in the growth performance among all treatments. Supplementation of the mixture of BA and SC increased acetate and propionate and decreased the E. coli in ceca compared to control and antibiotic treatment. The treatments with antibiotic, BA, and the mixture of BA and SC compared to control treatment increased villus height / crypt depth ratio and decreased ammonia in excreta. In addition, supplementation of BA and the mixture of BA and SC compared to antibiotic treatment increased serum high-density lipoprotein, and decreased serum glutamic-oxaloacetic transaminase, respectively. In conclusion, supplementation of the mixture of BA and SC was better than added BA only, and the mixed probiotics product could potentially alter the use of avilamycin in broiler diets.

Identification of fungal proteases potentially suitable for environmentally friendly cleaning-in-place in the dairy industry

Fourteen fungi were screened for ability to produce proteases with activity on milk protein. The proteases produced were assessed on a lab-scale in terms of their potential suitability for cleaning-in-place (CIP) in the dairy industry. Cleaning performance was assessed by determining the ability of the enzymes to remove an industrial-like milk fouling deposit from stainless steel. Based on the results observed, the extracellular protease activity produced by Schizophyllum commune was selected as most suitable for potential CIP application. A CIP procedure involving a sodium carbonate rinse followed by enzymatic cleaning with this fungal enzyme activity was developed. Satisfactory cleaning, judged by quantification of residual organic matter and protein on the stainless steel surface after cleaning, was achieved using the developed CIP procedure at 40°C. This CIP procedure, based on biodegradable enzymes working at low temperature is more environmentally favourable than conventional CIP methods using caustic based cleaning solutions at 70-80°C. Potential environmental benefits of the developed enzymatic CIP procedure include reduced energy consumption, decreased chemical usage and a reduced requirement for pH neutralisation of the resultant waste prior to release.