Determination of pregastric lipase specificity in young ruminants

Application of Goat and Lamb Lipases on the Development of New Immobilized Biocatalysts Aiming at Fish Oil Hydrolysis

The use of lipases from animal sources for the synthesis of new biocatalysts is barely studied in the literature. The present work focused on the immobilization of lipases from kid goat's and lamb's epiglottis in different ionic supports. For this, anionic supports (monoaminoethyl-N-aminoethyl-agarose (MANAE) and diethylaminoethyl-agarose (DEAE)) and cationic supports (carboxymethyl-agarose and sulfopropyl-agarose) were used. The immobilization parameters were evaluated, as well as the thermal stability of the immobilized enzymes and their stability at different values of pH. Then, the performance of the biocatalysts was evaluated in hydrolysis reactions for obtaining omega-3 fatty acids from fish oil (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)). Values of 100% of recovered activity were obtained for lipase from goats, indicating that it was possible to maintain all the enzymatic activities of the immobilized enzymes on the supports. The immobilized enzymes were more stable in different pH conditions and at a temperature of 50 °C, reaching values of stabilization factor of 12.17 and t1/2 of 9.86 h-1, for lamb lipase immobilized in sulfopropyl agarose. In general, the anionic supports led to lower Km values and the cationic ones to a higher Vmax. Lamb lipase showed the highest selectivity values for EPA/DHA, reaching values of 6.43 using MANAE. Thus, the high potential for using such biocatalysts from animal sources in the food or pharmaceutical industries is observed.

Supplementation of Bile Acids and Lipase in Broiler Diets for Better Nutrient Utilization and Performance: Potential Effects and Future Implications – A Review

Bile acids are used for better emulsification, digestion and absorption of dietary fat in chicken, especially in early life. Similarly, exogenous lipases have also been used for the improvement of physiological limitation of the chicken digestive system. Owing to potential of both bile acids and lipases, their use has been increased in recent years, for better emulsification of dietary fat and improvement of growth performance in broilers. In the past, pancreatic lipases were used for supplementation, but recently, microbial lipase is getting attention in poultry industry as a hydrolysis catalyst. Bile acids strengthen the defence mechanism of body against bacterial endotoxins and also play a key role in lipid regulation and sugar metabolism as signaling molecules. It has been demonstrated that bile acids and lipases may improve feed efficiency by enhancing digestive enzyme activity and ultimately leading to better fat digestion and absorption. Wide supplemental range of bile acids (0.004% to 0.25%) and lipases (0.01% to 0.1%) has been used in broiler diets for improvement of fat digestibility and their performance. Combinations of different bile acids have shown more potential to improve feed efficiency (by 7.14%) even at low (0.008%) levels as compared to any individual bile acid. Lipases at a lower level of 0.03% have exhibited more promising potential to improve fat digestibility and feed efficiency. However, contradicting results have been published in literature, which needs further investigations to elucidate various nutritional aspects of bile acids and lipase supplementation in broiler diet. This review focuses on providing insight on the mechanism of action and potential application of bile acids and lipases in broiler diets. Moreover, future implications of these additives in poultry nutrition for enhancing nutrient utilization and absorption are also discussed.

Relevant pH and lipase for in vitro models of gastric digestion

The development of in vitro digestion models relies on the availability of in vivo data such as digestive enzyme levels and pH values recorded in the course of meal digestion. The variations of these parameters along the GI tract are important for designing dynamic digestion models but also static models for which the choice of representative conditions of the gastric and intestinal conditions is critical. Simulating gastric digestion with a static model and a single set of parameters is particularly challenging because the variations in pH and enzyme concentration occurring in the stomach are much broader than those occurring in the small intestine. A review of the literature on this topic reveals that most models of gastric digestion use very low pH values that are not representative of the fed conditions. This is illustrated here by showing the variations in gastric pH as a function of meal gastric emptying instead of time. This representation highlights those pH values that are the most relevant for testing meal digestion in the stomach. Gastric lipolysis is still largely ignored or is performed with microbial lipases. In vivo data on gastric lipase and lipolysis have however been collected in humans and dogs during test meals. The biochemical characterization of gastric lipase has shown that this enzyme is rather unique among lipases: (i) stability and activity in the pH range 2 to 7 with an optimum at pH 4-5.4; (ii) high tensioactivity that allows resistance to bile salts and penetration into phospholipid layers covering TAG droplets; (iii) sn-3 stereospecificity for TAG hydrolysis; and (iv) resistance to pepsin. Most of these properties have been known for more than two decades and should provide a rational basis for the replacement of gastric lipase by other lipases when gastric lipase is not available.

Effects of inhomogeneity on triglyceride digestion of emulsions using an in vitro digestion model (Tiny TIM)

The concentration of fatty acids in the small intestine duringin vitrodigestion of emulsions is reported.

The products from lipase-catalysed hydrolysis of bovine milkfat killHelicobacter pylori in vitro

Free fatty acids and monoglycerides released from milkfat by partial pregastric lipase-catalysed hydrolysis are bactericidal towards Helicobacter pylori. Two milkfat preparations were investigated: a normal bovine milkfat, and a fractionated milkfat preparation, termed ModFat, enriched in triglycerides containing short- and medium-chain fatty acids. The released products were tested for bactericidal potency against H. pylori. The potencies of the respective preparations were consistent with expected potencies calculated from individual free fatty acid and monoglyceride concentrations and their lauric acid equivalence factors (Ki). ModFat products were more bactericidal, in accordance with release of free fatty acid types of high potency, and addition of the surfactant Tween 80 to the hydrolysed lipid increased potency eight times more than did addition of lecithin. Tween 80 micelles have smaller aggregation numbers, and the mixed micelles of Tween 80/free fatty acids would be more likely to expose the bacteria to higher apparent free fatty acid concentrations.

Purification and Characterization of a Pregastric Esterase From a Hygienized Kid Rennet Paste

Rennet pastes obtained by maceration of gastric tissues from suckling kids are used traditionally to produce some artisanal cheeses in Spain. Besides milk-clotting function, rennet pastes provide proteolytic activity and lipolytic system, essentially pregastric, necessary in the development of piquant flavor typical of these cheeses. A simple and reproducible procedure allows us to obtain a standardized rennet paste that posses the desired activity and is of good microbiological quality. Concomitantly, a kid pregastric esterase (KPGE) was purified to homogeneity. The purification procedure was based on an aqueous extract of hygienized rennet paste (HRP), which was chromatographed on DEAE-Sepharose Fast Flow then adsorbed on phenyl superose followed by a re-chromatography on the same column. The final enzymatic preparation, where the overall activity recovery was 3%, showed a molecular mass of 53 kDa. The highest activity was determined on p-nitrophenyl butyrate, but marked hydrolysis was also detected on beta-naphthyl caprylate. In contrast, low activity on tributyrin (substrate under emulsion form) was detected, thus confirming the esterase character of purified enzyme.

Early weaning of calves using feedstuffs. A rationalization based on inhibition of lipolysis

The ability of broll (a combination of the wheat-milling byproducts bran and pollard, i.e., a mixture of wheat bran, husk, and flour) and blackstrap molasses (an ingredient of calf feed) to inhibit calf pregastric lipase (CPGL)-catalyzed hydrolysis of tributyrylglycerol (TBG) has been studied in vitro. Lipolysis was measured at pH 6.5 and 37 degrees C (CPGL at 0.02 mg/mL) with stirring at 300 rpm. The broll soaked in Bis-Tris buffer (50 mM, pH 6.5) at 4 degrees C for either 24 h or 15 min, and then added to an emulsion containing TBG, before initiation of the reaction by addition of CPGL, exhibited 22% inhibitory effect. A solution of blackstrap molasses (50%, v/v) exhibited inhibitory effects of 50% in the absence and 45% in the presence of Bis-Tris buffer. The initial rate of lipolysis in the presence of the dialyzed molasses retentate (10%, v/v) increased a little, compared with the same amount of crude molasses, from a mean value of 69% to a mean value of 74%. The results have been discussed in terms of the chemical nature and composition of broll and molasses and their roles as components of feedstuffs used in development of the rumen in early weaning of calves.