Over the last decade, interest has increased when it comes to using temperate forage legumes cont... more Over the last decade, interest has increased when it comes to using temperate forage legumes containing condensed tannins (CT) for ruminants. The reason for this is that CT have been shown to benefit animal health and performance, as CT reduce parasitic burden by gastrointestinal nematodes, prevent bloat and reduce urinary nitrogen losses. Less is known about their impact on the quality of ruminant-based products. This short review discusses various quality issues which could, based on the current knowledge on the mode of action of CT, be positively affected by forages that are rich in CT. The main focus is the fatty acid composition, as well as the sensory traits of the meat, milk and cheese. The results presented here show the potential for two tanniferous forage legumes to positively affect the deposition of polyunsaturated fatty acids (PUFA), especially the n-3 fatty acids in meat, milk and cheese, and to improve the organoleptic quality of these products. From the two plants tested (birdsfoot trefoil and sainfoin), it is evident the CT effect in the digestive tract depends on various factors like the CT level, the chemical composition of the CT and whether the CT in the plant are available in a soluble form or bound to proteins or carbohydrates of the plants.
Pendant le prefanage et l’ensilage du fourrage, les proteines se degradent. Cette degradation a u... more Pendant le prefanage et l’ensilage du fourrage, les proteines se degradent. Cette degradation a un impact sur les differentes fractions de proteines. En plus des conditions d’ensilage, les composants secondaires des plantes exercent aussi une influence sur les fractions de proteines. Dans cet essai, l’influence de la conservation sur les fractions de proteines de trois legumineuses (luzerne, trefle violet et esparcette) lors du premier et du troisieme cycle a ete etudiee. A cet effet, des echantillons de fourrage frais, prefane et ensile ont ete preleves. Quelle que soit la variete de legumineuses, la proportion d’azote non proteique (NPN, fraction A) augmente considerablement dans le fourrage prefane et ensile. La luzerne a enregistre l’augmentation relative la plus importante de la fraction NPN: la proportion de celle-ci dans l’ensilage etait 60 % plus elevee que dans l’ensilage de trefle violet et d’esparcette. Il est probable que la degradation reduite des proteines dans l’esparcette soit due aux tanins condenses et a l’activite de l’oxydase des polyphenols dans le trefle violet.
Condensed tannins (CT) in legume forages vary not only in concentration and structure, but also i... more Condensed tannins (CT) in legume forages vary not only in concentration and structure, but also in the portion of soluble and protein-and fibre-bound fractions. This study aimed to assess the changes in the total CT level as well as relative abundance of the three CT fractions from fresh to wilted, ensiled or pelleted legumes like in birds foot trefoil (two cultivars) and in sainfoin (one cultivar). Each legume underwent three consecutive harvests, of which the first two were wilted. Additionally, wilted legumes were either ensiled (first harvest) or transformed into dehydrated pellets (second harvest). For each harvest, total CT and the percentage of soluble, protein-and fibre-bound CT differed (P < 0.01) among plants. The total CT content was similar after wilting but was lower (P < 0.05) after ensiling. After wilting, ensiling and pelleting the portion of soluble CT was lower in favour of protein-bound CT portion. However, time of harvest affected (P < 0.05) total CT and the percentage of soluble and protein-bound CT. Thus, measuring the bound-fraction should not be ignored in the determination of CT content since this fraction, together with the soluble fraction, might protect protein from ruminal degradation.
The extensive protein degradation occurring during ensiling decreases the nutritive value of sila... more The extensive protein degradation occurring during ensiling decreases the nutritive value of silages, but this might be counteracted by tannins. Therefore, silages from two legume species containing condensed tannins (CT)sainfoin (SF) and birdsfoot trefoil (two cultivars: birdsfoot trefoil, cv. Bull (BTB) and birdsfoot trefoil, cv. Polom)were compared for their in vitro ruminal fermentation characteristics. The effect of combining them with two CT-free legume silages (lucerne (LU) and red clover (RC)) was also determined. The supply of duodenally utilisable CP (uCP) in the forages was emphasised. The legumes were each harvested from three field sites. After 24 h of wilting on the field, the legumes were ensiled in laboratory silos for 86 days. Proximate constituents, silage fermentation characteristics, CT content and CP fractions were determined. Subsequently, silage samples and 1 : 1 mixtures of the CT-containing and CT-free silages were incubated for 24 h in batch cultures using ruminal fluid and buffer (1 : 2, v/v). Each treatment was replicated six times in six runs. The effects on pH, ammonia and volatile fatty acid concentrations, protozoal counts, and total gas and methane production were determined. uCP content was calculated by considering the CP in the silage and the ammonia in the incubation fluid from treatments and blanks. Statistical evaluation compared data from single plants alone and together with that from the mixtures. Among treatments, SF silage contained the least CP and the most CT. The non-protein nitrogen content was lower, favouring neutral detergent soluble and insoluble protein fractions, in the SF and RC silages. Absolute uCP content was lowest in SF and SF mixtures, although the ratio to total CP was the highest. In comparison with LU, the ammonia concentration of the incubation fluid was lower for SF, RC and BTB and for the mixture of SF with LU. The total gas and methane production was similar among the treatments, and the total volatile fatty acid production was decreased with the CT-containing legumes. Protozoal count was increased with the mixtures containing LU and either SF or BTB compared with single LU. In conclusion, compared with the other legumes, SF and RC have similar advantages as they show limited proteolysis during ensiling. In addition, SF supplies more uCP relative to total CP. The CT-containing legumes also differed in their effect on ruminal fermentation and ammonia formation, probably because of their different CT contents. Thus, SF and its mixtures appear promising for improving the protein utilisation of ruminants.
L’amelioration de la prolificite des truies a permis d’augmenter significativement le nombre de p... more L’amelioration de la prolificite des truies a permis d’augmenter significativement le nombre de porcelets par nichee. Mais, parallelement la proportion de porcelets de faible poids a aussi augmente. Il en resulte un poids moyen de la nichee plus bas et des nichees beaucoup plus heterogenes, avec des porcelets de moins d’un kilo et d’autres pesant plus de deux kilos au sein de la meme nichee. Les porcelets nes legers disposent de moins de reserves corporelles et sont moins competitifs pour les meilleures tetines. Par consequent, les performances ulterieures sont compromises et le risque de morbidite et de mortalite reste eleve chez ces animaux, ce qui engendre des pertes considerables pour les eleveurs. Dans ce contexte, il est primordial d’ameliorer la survie et renforcer le developpement de ces porcelets.
In addition to a multifactorial etiology of nutritional, social and environmental stressors, post... more In addition to a multifactorial etiology of nutritional, social and environmental stressors, post-weaning diarrhea (PWD) in pigs is often related to infection with specific pathogens such as enterotoxigenic Escherichia coli (ETEC). In swine farming operations, the incidence of PWD is a global concern and is associated with an unbalanced gut status, resulting in poor performance and high antimicrobial consumption via prophylaxis and metaphylaxis. Increases in antimicrobial resistance are reinforcing an alreadyurgent need for sustainable, alternative solutions for maintaining optimal gut health in livestock. Tannin-rich plants and extracts contain bioactive compounds that could be of great interest in this respect. This review describes how the use of tannins around weaning could be beneficial for pigs, with special emphasis on the reduction of ETEC-related PWD. An overview of the broad chemical diversity of tannins is presented together with their physicochemical and biological properties, as well as how they may be metabolized in the digestive tract. The pharmacological effects exerted by tannins are summarized; more precisely, the possible mechanisms by which tannins can disrupt the different steps of the pathogenesis of ETEC-related PWD are highlighted. The factors affecting the bioactivity of tannins are also discussed, shedding light on the importance of chemical structure among different tannins.
Hemicelluloses (HC) are polysaccharides constituents of the cell walls of plants. They are fermen... more Hemicelluloses (HC) are polysaccharides constituents of the cell walls of plants. They are fermented in the gut to produce volatile fatty acids (VFA). The present study investigated the effects of decreasing HC level in sow's lactation diet on sow performances, offspring development and milk composition. From 110 days (d) of gestation until weaning (26±0.4 d post-farrowing), 40 Swiss Large White sows were assigned to one of the four dietary treatments: (1) T12 (HC: 120.6g/kg), (2) T11 (HC: 107.6 g/kg), (3) T9 (HC: 86.4g/kg) and (4) T7 (HC: 71.9g/kg). Milk was collected at 3 and 17d of lactation. At birth, piglets were divided into two groups according to their birthweight (BtW): normal (N-BtW; BtW > 1.20 kg) or low (L-BtW; BtW ≤ 1.20 kg). Decreased HC levels in the maternal diet linearly increased (P ≤ 0.05) the body weight of L-BtW piglets at two weeks post-weaning and linearly decreased (P ≤ 0.05) diarrhoea incidence and duration in this category. The concentrations of copper, threonine and VFA, as well as the proportion of butyrate, in milk linearly increased (P ≤ 0.05), whereas lactose content linearly decreased (P ≤ 0.05) with decreased HC in the maternal diet. The present study provides evidence that decreasing HC level in sow's lactation diet can positively affect the composition and VFA profile of milk and ultimately favour the growth and health of L-BtW piglets.
The development of alternatives to antibiotics is crucial to limiting the incidence of antimicrob... more The development of alternatives to antibiotics is crucial to limiting the incidence of antimicrobial resistance, especially in prophylactic and metaphylactic use to control post-weaning diarrhea (PWD). Feed additives, including bioactive compounds, could be a promising alternative. This study aimed to test two bioactive compounds, sodium salicylate (SA) and a chestnut extract (CE) containing hydrolysable tannins, on the occurrence of PWD. At weaning, 72 piglets were assigned to four treatments that combined two factors: CE supplementation (with 2% of CE (CE+) or without (CE-)) and SA supplementation (with 35 mg/kg BW of SA (SA+) or without (SA-)). Then, 4 days after weaning, all piglets were infected with a suspension at 10 8 CFU/ml of enterotoxigenic Escherichia coli (ETEC F4ac). Each piglet had free access to an electrolyte solution containing, or not, SA. This SA supplementation was administered for 5 days (i.e., from the day of infection (day 0) to 4 days post-infection (day 4). During the 2 weeks postinfection, supplementation with SA had no effect (P > 0.05) on growth performances nor on fecal scores. A significant SA × time interaction (P < 0.01) for fecal scores and the percentage of diarrhea indicated that piglets with SA did not recover faster and did have a second episode of diarrhea. In contrast to SA treatment, inclusion of CE increased (P < 0.05) growth performances and feed intake. In the first week post-infection, CE decreased (P < 0.001) the overall fecal scores, the percentage of piglets with diarrhea, the days in diarrhea, and ETEC shedding in the feces. There was a SA×CE interaction (P < 0.05) for ETEC shedding, suggesting a negative effect of combining SA with CE. This study highlighted that, in contrast to SA, CE could represent a promising alternative to antibiotics immediately after weaning for improving growth performance and reducing PWD. .
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Journal of Agricultural and Food Chemistry, Oct 20, 2015
Little information exists on the effects of ensiling on condensed tannins or proanthocyanidins. T... more Little information exists on the effects of ensiling on condensed tannins or proanthocyanidins. The acetone−butanol−HCl assay is suitable for measuring proanthocyanidin contents in a wide range of samples, silages included, but provides limited information on proanthocyanidin composition, which is of interest for deciphering the relationships between tannins and their bioactivities in terms of animal nutrition or health. Degradation with benzyl mercaptan (thiolysis) provides information on proanthocyanidin composition but proanthocyanidins in several sainfoin silages have proved resistant to thiolysis. We now report that a pretreatment step with sodium hydroxide prior to thiolysis was needed to enable their analysis. This alkaline treatment increased their extractability from ensiled sainfoin and facilitated especially the release of larger proanthocyanidins. Ensiling reduced assayable proanthocyanidins by 29% but the composition of the remaining proanthocyanidins in silage resembled those of the fresh plants.
Condensed tannins (CT) may affect ruminal biohydrogenation of dietary polyunsaturated fatty acids... more Condensed tannins (CT) may affect ruminal biohydrogenation of dietary polyunsaturated fatty acids. A feeding experiment was conducted with 24 Holstein cows to evaluate whether diets containing CT from different forage legumes can increase polyunsaturated fatty acids, especially n-3 fatty acid content in milk and cheese, without affecting negatively their physicochemical and sensorial properties. Cows were assigned to 4 treatment groups (n = 6) for 52 d, divided into 2 periods: a control period (CoP) and an experimental period (ExP). During the CoP, cows received a basal diet composed of hay, corn silage, ExtruLin (Trinova Handel & Marketing AG, Wangen, Switzerland), concentrate, and alfalfa (AF) in a ratio of 45:25:5:7:18. In the ExP, in 3 of the 4 groups AF was replaced by either sainfoin (SF; 19% CT in dry matter) or 1 of 2 cultivars of birdsfoot trefoil [Polom (BP), 3% CT; Bull (BB), 5% CT]. At the end of each period, milk was collected on 3 consecutive days and analyzed for milk gross composition and fatty acid profile and was processed to Gruyère-type cheese. A trained panel assessed the sensory quality of raw milk and cheese using discriminative and descriptive tests. This experimental design consisting of AF in both the CoP and ExP allowed us to quantify effects due to lactation stage and experimental diets. In both the CoP and ExP, dry matter intake and milk yield did not differ among treatment groups. From the CoP to the ExP, milk urea content was reduced by 23% with SF, remained unchanged with BP, and tended to increase with AF and BB. The odor of the raw BB milk was judged to be different from AF milk. With SF, switching from the CoP to the ExP resulted in a 17% increase of the 18:3n-3 proportion in milk and cheese lipids. In BP cheese, the increase was 3%, whereas it tended to decrease in BB cheese. Additionally, the 20:5n-3 and 22:5n-3 proportions tended to increase in SF cheese from the CoP to the ExP. Compared with the AF cheeses, cheeses from cows fed CT-containing legumes were judged harder and tended to be less adhesive to the palate. In addition, SF and BP cheeses had less rind. In conclusion, feeding SF compared with BB and BP increased the content of 18:3n-3 in the milk and the cheese without a negative effect on flavor of the cheese. Despite a similar CT content, the 2 birdsfoot trefoil cultivars had opposite effects on milk urea and 18:3n-3 deposition, suggesting that, besides the content, the chemical structure may have had an important effect on the CT efficacy.
Over the last decade, interest has increased when it comes to using temperate forage legumes cont... more Over the last decade, interest has increased when it comes to using temperate forage legumes containing condensed tannins (CT) for ruminants. The reason for this is that CT have been shown to benefit animal health and performance, as CT reduce parasitic burden by gastrointestinal nematodes, prevent bloat and reduce urinary nitrogen losses. Less is known about their impact on the quality of ruminant-based products. This short review discusses various quality issues which could, based on the current knowledge on the mode of action of CT, be positively affected by forages that are rich in CT. The main focus is the fatty acid composition, as well as the sensory traits of the meat, milk and cheese. The results presented here show the potential for two tanniferous forage legumes to positively affect the deposition of polyunsaturated fatty acids (PUFA), especially the n-3 fatty acids in meat, milk and cheese, and to improve the organoleptic quality of these products. From the two plants tested (birdsfoot trefoil and sainfoin), it is evident the CT effect in the digestive tract depends on various factors like the CT level, the chemical composition of the CT and whether the CT in the plant are available in a soluble form or bound to proteins or carbohydrates of the plants.
Pendant le prefanage et l’ensilage du fourrage, les proteines se degradent. Cette degradation a u... more Pendant le prefanage et l’ensilage du fourrage, les proteines se degradent. Cette degradation a un impact sur les differentes fractions de proteines. En plus des conditions d’ensilage, les composants secondaires des plantes exercent aussi une influence sur les fractions de proteines. Dans cet essai, l’influence de la conservation sur les fractions de proteines de trois legumineuses (luzerne, trefle violet et esparcette) lors du premier et du troisieme cycle a ete etudiee. A cet effet, des echantillons de fourrage frais, prefane et ensile ont ete preleves. Quelle que soit la variete de legumineuses, la proportion d’azote non proteique (NPN, fraction A) augmente considerablement dans le fourrage prefane et ensile. La luzerne a enregistre l’augmentation relative la plus importante de la fraction NPN: la proportion de celle-ci dans l’ensilage etait 60 % plus elevee que dans l’ensilage de trefle violet et d’esparcette. Il est probable que la degradation reduite des proteines dans l’esparcette soit due aux tanins condenses et a l’activite de l’oxydase des polyphenols dans le trefle violet.
Condensed tannins (CT) in legume forages vary not only in concentration and structure, but also i... more Condensed tannins (CT) in legume forages vary not only in concentration and structure, but also in the portion of soluble and protein-and fibre-bound fractions. This study aimed to assess the changes in the total CT level as well as relative abundance of the three CT fractions from fresh to wilted, ensiled or pelleted legumes like in birds foot trefoil (two cultivars) and in sainfoin (one cultivar). Each legume underwent three consecutive harvests, of which the first two were wilted. Additionally, wilted legumes were either ensiled (first harvest) or transformed into dehydrated pellets (second harvest). For each harvest, total CT and the percentage of soluble, protein-and fibre-bound CT differed (P < 0.01) among plants. The total CT content was similar after wilting but was lower (P < 0.05) after ensiling. After wilting, ensiling and pelleting the portion of soluble CT was lower in favour of protein-bound CT portion. However, time of harvest affected (P < 0.05) total CT and the percentage of soluble and protein-bound CT. Thus, measuring the bound-fraction should not be ignored in the determination of CT content since this fraction, together with the soluble fraction, might protect protein from ruminal degradation.
The extensive protein degradation occurring during ensiling decreases the nutritive value of sila... more The extensive protein degradation occurring during ensiling decreases the nutritive value of silages, but this might be counteracted by tannins. Therefore, silages from two legume species containing condensed tannins (CT)sainfoin (SF) and birdsfoot trefoil (two cultivars: birdsfoot trefoil, cv. Bull (BTB) and birdsfoot trefoil, cv. Polom)were compared for their in vitro ruminal fermentation characteristics. The effect of combining them with two CT-free legume silages (lucerne (LU) and red clover (RC)) was also determined. The supply of duodenally utilisable CP (uCP) in the forages was emphasised. The legumes were each harvested from three field sites. After 24 h of wilting on the field, the legumes were ensiled in laboratory silos for 86 days. Proximate constituents, silage fermentation characteristics, CT content and CP fractions were determined. Subsequently, silage samples and 1 : 1 mixtures of the CT-containing and CT-free silages were incubated for 24 h in batch cultures using ruminal fluid and buffer (1 : 2, v/v). Each treatment was replicated six times in six runs. The effects on pH, ammonia and volatile fatty acid concentrations, protozoal counts, and total gas and methane production were determined. uCP content was calculated by considering the CP in the silage and the ammonia in the incubation fluid from treatments and blanks. Statistical evaluation compared data from single plants alone and together with that from the mixtures. Among treatments, SF silage contained the least CP and the most CT. The non-protein nitrogen content was lower, favouring neutral detergent soluble and insoluble protein fractions, in the SF and RC silages. Absolute uCP content was lowest in SF and SF mixtures, although the ratio to total CP was the highest. In comparison with LU, the ammonia concentration of the incubation fluid was lower for SF, RC and BTB and for the mixture of SF with LU. The total gas and methane production was similar among the treatments, and the total volatile fatty acid production was decreased with the CT-containing legumes. Protozoal count was increased with the mixtures containing LU and either SF or BTB compared with single LU. In conclusion, compared with the other legumes, SF and RC have similar advantages as they show limited proteolysis during ensiling. In addition, SF supplies more uCP relative to total CP. The CT-containing legumes also differed in their effect on ruminal fermentation and ammonia formation, probably because of their different CT contents. Thus, SF and its mixtures appear promising for improving the protein utilisation of ruminants.
L’amelioration de la prolificite des truies a permis d’augmenter significativement le nombre de p... more L’amelioration de la prolificite des truies a permis d’augmenter significativement le nombre de porcelets par nichee. Mais, parallelement la proportion de porcelets de faible poids a aussi augmente. Il en resulte un poids moyen de la nichee plus bas et des nichees beaucoup plus heterogenes, avec des porcelets de moins d’un kilo et d’autres pesant plus de deux kilos au sein de la meme nichee. Les porcelets nes legers disposent de moins de reserves corporelles et sont moins competitifs pour les meilleures tetines. Par consequent, les performances ulterieures sont compromises et le risque de morbidite et de mortalite reste eleve chez ces animaux, ce qui engendre des pertes considerables pour les eleveurs. Dans ce contexte, il est primordial d’ameliorer la survie et renforcer le developpement de ces porcelets.
In addition to a multifactorial etiology of nutritional, social and environmental stressors, post... more In addition to a multifactorial etiology of nutritional, social and environmental stressors, post-weaning diarrhea (PWD) in pigs is often related to infection with specific pathogens such as enterotoxigenic Escherichia coli (ETEC). In swine farming operations, the incidence of PWD is a global concern and is associated with an unbalanced gut status, resulting in poor performance and high antimicrobial consumption via prophylaxis and metaphylaxis. Increases in antimicrobial resistance are reinforcing an alreadyurgent need for sustainable, alternative solutions for maintaining optimal gut health in livestock. Tannin-rich plants and extracts contain bioactive compounds that could be of great interest in this respect. This review describes how the use of tannins around weaning could be beneficial for pigs, with special emphasis on the reduction of ETEC-related PWD. An overview of the broad chemical diversity of tannins is presented together with their physicochemical and biological properties, as well as how they may be metabolized in the digestive tract. The pharmacological effects exerted by tannins are summarized; more precisely, the possible mechanisms by which tannins can disrupt the different steps of the pathogenesis of ETEC-related PWD are highlighted. The factors affecting the bioactivity of tannins are also discussed, shedding light on the importance of chemical structure among different tannins.
Hemicelluloses (HC) are polysaccharides constituents of the cell walls of plants. They are fermen... more Hemicelluloses (HC) are polysaccharides constituents of the cell walls of plants. They are fermented in the gut to produce volatile fatty acids (VFA). The present study investigated the effects of decreasing HC level in sow's lactation diet on sow performances, offspring development and milk composition. From 110 days (d) of gestation until weaning (26±0.4 d post-farrowing), 40 Swiss Large White sows were assigned to one of the four dietary treatments: (1) T12 (HC: 120.6g/kg), (2) T11 (HC: 107.6 g/kg), (3) T9 (HC: 86.4g/kg) and (4) T7 (HC: 71.9g/kg). Milk was collected at 3 and 17d of lactation. At birth, piglets were divided into two groups according to their birthweight (BtW): normal (N-BtW; BtW > 1.20 kg) or low (L-BtW; BtW ≤ 1.20 kg). Decreased HC levels in the maternal diet linearly increased (P ≤ 0.05) the body weight of L-BtW piglets at two weeks post-weaning and linearly decreased (P ≤ 0.05) diarrhoea incidence and duration in this category. The concentrations of copper, threonine and VFA, as well as the proportion of butyrate, in milk linearly increased (P ≤ 0.05), whereas lactose content linearly decreased (P ≤ 0.05) with decreased HC in the maternal diet. The present study provides evidence that decreasing HC level in sow's lactation diet can positively affect the composition and VFA profile of milk and ultimately favour the growth and health of L-BtW piglets.
The development of alternatives to antibiotics is crucial to limiting the incidence of antimicrob... more The development of alternatives to antibiotics is crucial to limiting the incidence of antimicrobial resistance, especially in prophylactic and metaphylactic use to control post-weaning diarrhea (PWD). Feed additives, including bioactive compounds, could be a promising alternative. This study aimed to test two bioactive compounds, sodium salicylate (SA) and a chestnut extract (CE) containing hydrolysable tannins, on the occurrence of PWD. At weaning, 72 piglets were assigned to four treatments that combined two factors: CE supplementation (with 2% of CE (CE+) or without (CE-)) and SA supplementation (with 35 mg/kg BW of SA (SA+) or without (SA-)). Then, 4 days after weaning, all piglets were infected with a suspension at 10 8 CFU/ml of enterotoxigenic Escherichia coli (ETEC F4ac). Each piglet had free access to an electrolyte solution containing, or not, SA. This SA supplementation was administered for 5 days (i.e., from the day of infection (day 0) to 4 days post-infection (day 4). During the 2 weeks postinfection, supplementation with SA had no effect (P > 0.05) on growth performances nor on fecal scores. A significant SA × time interaction (P < 0.01) for fecal scores and the percentage of diarrhea indicated that piglets with SA did not recover faster and did have a second episode of diarrhea. In contrast to SA treatment, inclusion of CE increased (P < 0.05) growth performances and feed intake. In the first week post-infection, CE decreased (P < 0.001) the overall fecal scores, the percentage of piglets with diarrhea, the days in diarrhea, and ETEC shedding in the feces. There was a SA×CE interaction (P < 0.05) for ETEC shedding, suggesting a negative effect of combining SA with CE. This study highlighted that, in contrast to SA, CE could represent a promising alternative to antibiotics immediately after weaning for improving growth performance and reducing PWD. .
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Journal of Agricultural and Food Chemistry, Oct 20, 2015
Little information exists on the effects of ensiling on condensed tannins or proanthocyanidins. T... more Little information exists on the effects of ensiling on condensed tannins or proanthocyanidins. The acetone−butanol−HCl assay is suitable for measuring proanthocyanidin contents in a wide range of samples, silages included, but provides limited information on proanthocyanidin composition, which is of interest for deciphering the relationships between tannins and their bioactivities in terms of animal nutrition or health. Degradation with benzyl mercaptan (thiolysis) provides information on proanthocyanidin composition but proanthocyanidins in several sainfoin silages have proved resistant to thiolysis. We now report that a pretreatment step with sodium hydroxide prior to thiolysis was needed to enable their analysis. This alkaline treatment increased their extractability from ensiled sainfoin and facilitated especially the release of larger proanthocyanidins. Ensiling reduced assayable proanthocyanidins by 29% but the composition of the remaining proanthocyanidins in silage resembled those of the fresh plants.
Condensed tannins (CT) may affect ruminal biohydrogenation of dietary polyunsaturated fatty acids... more Condensed tannins (CT) may affect ruminal biohydrogenation of dietary polyunsaturated fatty acids. A feeding experiment was conducted with 24 Holstein cows to evaluate whether diets containing CT from different forage legumes can increase polyunsaturated fatty acids, especially n-3 fatty acid content in milk and cheese, without affecting negatively their physicochemical and sensorial properties. Cows were assigned to 4 treatment groups (n = 6) for 52 d, divided into 2 periods: a control period (CoP) and an experimental period (ExP). During the CoP, cows received a basal diet composed of hay, corn silage, ExtruLin (Trinova Handel & Marketing AG, Wangen, Switzerland), concentrate, and alfalfa (AF) in a ratio of 45:25:5:7:18. In the ExP, in 3 of the 4 groups AF was replaced by either sainfoin (SF; 19% CT in dry matter) or 1 of 2 cultivars of birdsfoot trefoil [Polom (BP), 3% CT; Bull (BB), 5% CT]. At the end of each period, milk was collected on 3 consecutive days and analyzed for milk gross composition and fatty acid profile and was processed to Gruyère-type cheese. A trained panel assessed the sensory quality of raw milk and cheese using discriminative and descriptive tests. This experimental design consisting of AF in both the CoP and ExP allowed us to quantify effects due to lactation stage and experimental diets. In both the CoP and ExP, dry matter intake and milk yield did not differ among treatment groups. From the CoP to the ExP, milk urea content was reduced by 23% with SF, remained unchanged with BP, and tended to increase with AF and BB. The odor of the raw BB milk was judged to be different from AF milk. With SF, switching from the CoP to the ExP resulted in a 17% increase of the 18:3n-3 proportion in milk and cheese lipids. In BP cheese, the increase was 3%, whereas it tended to decrease in BB cheese. Additionally, the 20:5n-3 and 22:5n-3 proportions tended to increase in SF cheese from the CoP to the ExP. Compared with the AF cheeses, cheeses from cows fed CT-containing legumes were judged harder and tended to be less adhesive to the palate. In addition, SF and BP cheeses had less rind. In conclusion, feeding SF compared with BB and BP increased the content of 18:3n-3 in the milk and the cheese without a negative effect on flavor of the cheese. Despite a similar CT content, the 2 birdsfoot trefoil cultivars had opposite effects on milk urea and 18:3n-3 deposition, suggesting that, besides the content, the chemical structure may have had an important effect on the CT efficacy.
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