Hiilihydraatteja pilkkovien entsyymien lisäys porsasrehuihin - stabiilisuus, aktiivisuus ja toimintatavat

A total of five experiments were conducted to investigate the stability of feed enzymes to steam pelleting and the proteolytic conditions in the gastrointestinal (GI) tract of pigs and poultry, and to try and elucidate the mechanisms behind the improved performance of pigs fed enzyme-supplemented barley/wheat-based diets. The results of the pelleting stability experiment showed that the commercial feed enzyme employed maintained most of its activity in conditioning temperatures up to 85°C.Furthermore, it became evident that measuring enzyme recovery in pelleted feeds by in-vitro assay methods underestimated the actual activity. For this purpose in-vivo models such as that based on gut viscosity measurements in broiler chickens gives a more accurate estimate. Gut viscosity also correlated highly with live weight gain (r2=0.624) and feed utilisation (r2=0.616) of broiler chickens. The in-vitro incubations using conditions similar to those of the GI tract showed that enzymes are not readily denatured and inactivated in such conditions and indicated that wheat and wheat gluten, and possibly similar feed ingredients, may help to maintain the activity longer either due to their buffering capacity or by providing substrates for the enzymes. This was supported by the results of the in-vivo measurements. In the stomach of pigs, 10-20per cent of the xylanase and β-glucanase activities added to the diets could still be recovered 4 hours after feeding. In the ileum, proportionally more added enzyme activities were recovered between 4 and 6 than 0 and 2 hours after feeding. In broiler chickens fed an enzyme-supplemented barley-based diet, β-glucanase was fully recovered in the proximal part of the small intestine, giving further proof of the stability of the enzymes employed to the conditions of the GI tract. When a mixture of fibre- and starch-degrading enzymes were added to a diet based on wheat and barley, β-glucan, starch and dry matter digestibilities were significantly (PRehuentsyymien stabiilisuutta rakeistuksessa sekä sian ja kanan ruoansulatuskanavaa muistuttavissa olosuhteissa tutkittiin in-vitro- ja in-vivo -menetelmiä käyttäen kaikkiaan kolmessa eri kokeessa. Entsyymilisäysten aikaansaamia porsaiden tuotantotuloksiin vaikuttavia tekijöitä tutkittiin lisäksi ohra- ja vehnäpohjaisilla rehuilla kahdessa eri kokeessa. Käytetyt rehuentsyymit säilyttivät rakeistuskokeiden tulosten mukaan aktiivisuutensa 85 °C:een asti. Käytetyn in-vitro -menetelmän todettiin aliarvioivan rakeistetussa rehussa säilyvää entsyymiaktiivisuutta. Broilereiden ohutsuolen sisällön viskositeetin mittaamiseen perustuva in-vivo -menetelmä soveltui paremmin tähän tarkoitukseen. Ohutsuolen sisällön viskositeetin, broilereiden kasvun (r2=0.624) ja rehun hyväksikäytön (r2=0.616) välillä todettiin voimakas negatiivinen korrelaatio. Ruoansulatuskanavaa jäljittelevissä olosuhteissa tehdyt in-vitro -inkuboinnit osoittivat entsyymien inaktivoitumisen olevan vähäistä. Lisäksi vehnä ja vehnägluteeni paransivat entsyymien stabiilisuutta niiden puskoroivien vaikutusten ansiosta tai toimimalla entsyymien kiinnityskohteina. Saadut tulokset olivat yhdenmukaisia broilereilla ja sioilla saatujen tulosten kanssa. Rehuun lisätty koko ksylanaasi- ja β-glukanaasimäärä säilyi sian mahalaukussa puolen tunnin ajan ruokinnasta ja 10-20% lisätystä entsyymimäärästä todettiin vielä 4 tuntia ruokinnan jälkeen. Lisätyistä entsyymeistä säilyi suurempi osuus 2-6 tuntia ruokinnan jälkeen kuin kahden ensimmäisen tunnin aikana. Ohrapohjaiseen rehuun lisätty β-glukanaasi säilyi kokonaisuudessaan broilerin ohutsuolessa. Nämä tulokset osoittavat, että käytetyt entsyymit kestävät ruoansulatuskanavan proteolyyttisiä olosuhteita suhteellisen hyvin. Porsaat sulattivat ohra- ja vehnäpohjaisten rehujen β-glukaania, tärkkelystä ja kuiva-ainetta paremmin (

Supplementation of pig starter diets with carbohydrate-degrading enzymes - stability, activity and mode of action

A total of five experiments were conducted to investigate the stability of feed enzymes to steam pelleting and the proteolytic conditions in the gastrointestinal (GI) tract of pigs and poultry, and to try and elucidate the mechanisms behind the improved performance of pigs fed enzyme-supplemented barley/wheat-based diets. The results of the pelleting stability experiment showed that the commercial feed enzyme employed maintained most of its activity in conditioning temperatures up to 85°C.Furthermore, it became evident that measuring enzyme recovery in pelleted feeds by in-vitro assay methods underestimated the actual activity. For this purpose in-vivo models such as that based on gut viscosity measurements in broiler chickens gives a more accurate estimate. Gut viscosity also correlated highly with live weight gain (r2=0.624) and feed utilisation (r2=0.616) of broiler chickens. The in-vitro incubations using conditions similar to those of the GI tract showed that enzymes are not readily denatured and inactivated in such conditions and indicated that wheat and wheat gluten, and possibly similar feed ingredients, may help to maintain the activity longer either due to their buffering capacity or by providing substrates for the enzymes. This was supported by the results of the in-vivo measurements. In the stomach of pigs, 10-20per cent of the xylanase and β-glucanase activities added to the diets could still be recovered 4 hours after feeding. In the ileum, proportionally more added enzyme activities were recovered between 4 and 6 than 0 and 2 hours after feeding. In broiler chickens fed an enzyme-supplemented barley-based diet, β-glucanase was fully recovered in the proximal part of the small intestine, giving further proof of the stability of the enzymes employed to the conditions of the GI tract. When a mixture of fibre- and starch-degrading enzymes were added to a diet based on wheat and barley, β-glucan, starch and dry matter digestibilities were significantly (

Industrial amino acids in diets for piglets and growing pigs

Two production trials with piglets and one with slaughter pigs were carried out in order to investigate the effects of reducing the protein content in the diets followed by an addition of industrial amino acids on performance and health status. In the first piglet trial the crude protein content of the control diet was decreased from 20 to 18.3 % and in the second from 18.3 to 16.7 %. In the trial with growing pigs, the protein content of the control diet was decreased from 17.0 to 15.5 %. Industrial L-lysine, DL-methionine and L-threonine were added to the low protein diets to get the same levels of these amino acids as in the control diets. Piglet performance was similar on all treatments indicating equal availability of added and protein-bound amino acids. Health status of piglets on the low protein diets was considerably improved, indicating less predisposition to post weaning diarrhoea. Pigs on the low protein amino acid fortified diet tended to gain weight faster (788 vs. 743 g/day;

Stability of feed enzymes in physiological conditions assayed by in vitro methods

A series of in vitro incubations were carried out to investigate the stability of two enzyme preparations in conditions similar to those in the upper gastrointestinal tract of monogastric animals. The two enzyme products, one crude xylanase from Trichoderma longibrachiatum (Multifekt K) and the other a specifically manufactured feed enzyme (Avizyme SX®), were subjected to incubations at low and neutral pH with and without proteolytic enzymes (pepsin and pancreatin). Wheat gluten was employed together with the crude xylanase to investigate its potential as a stabilising agent. Due to the buffering effect of Avizyme SX®, incubations were carried out with (pH 2.5) and without (pH 3.2) addition of either citric or hydrochloric acid. Incubation of the crude xylanase at low pH followed by incubation at neutral pH resulted in negligible loss of xylanase activity whereas β-xylosidase recovery fell to 57 per cent of the initial value (

The effect of enzyme treatment of cooked barley and supplementation of piglet diets on the digestibility of barley and piglet performance

A digestibility trial, designed as a 5*5 Latin square, with growing pigs was conducted to investigate the effect of cooking and enzyme treatment of barley on digestibility and nitrogen utilization. In addition, two piglet performance trials were conducted to investigate the effect of hydrothermal processing of barley and soybean meal and enzyme supplementation of piglet feeds on performance and health status. Five pigs, averaging 40 kg LW, were fitted with T-shaped cannulas in the terminal ileum and fed the experimental diets for five consequtive 12-day experimental periods. Chromic oxide was used as marker. Cooking of barley significantly improved the apparent faecal digestibility (AD) of DM, OM, CP and EE (