Agustín Viveros

Effect of Grape Pomace Concentrate and Vitamin E on Digestibility of Polyphenols and Antioxidant Activity in Chickens

Grape pomace provides a rich source of polyphenols that have the capacity to act as powerful antioxidants. An experiment was conducted to study the effect of inclusion of grape pomace concentrate (GPC) at levels of 15, 30, and 60 g/kg and alpha-tocopheryl acetate (200 mg/kg) in broiler chicks (21 to 42 d of age) on performance; digestive organ sizes; protein; fat; hydrolyzable polyphenol and condensed tannin digestibilities; the anti-oxidant activity of diet, serum, ileal content, and excreta; and the susceptibility to oxidation of breast meat during refrigerated storage. The inclusion of GPC did not affect the performance; the apparent ileal digestibility of CP; the relative abdominal fat, liver, pancreas, and spleen weight; and the relative intestinal length. Fat digestibility was reduced in birds fed control and GPC diets compared with birds fed vitamin E. Ileal and fecal digestibility of hydrolyzable polyphenols and condensed tannins reached values in a range of 56 to 73% and 14 to 47%, respectively. The GPC diets reduced ileal and fecal digestibility of hydrolyzable polyphenols. Antioxidant activity in GPC diet, ileal content, and excreta [2, 2-azinobis (3-ethilenzotiazolin)-6-sulfonate method] and GPC diet (ferric antioxidant power method) exhibited higher scavenging free radical capacity than control and vitamin E diets. The lipid oxidation in breast meat was lower in the birds fed the supplemented vitamin E diet than the control diet after 1, 4, and 7 d of refrigerated storage. Oxidative stability in breast meat at 1, 4, and 7 d of storage was equivalent in GPC diets compared with the vitamin E diet. In conclusion, the inclusion of GPC (up to 60 g/kg) did not impair chicken growth performance, digestive organ sizes, and protein digestibility. Hydrolyzable polyphenols were more bioavailable than condensed tannins. Antioxidant activity in diet, excreta, ileal content, and breast muscle were increased in GPC diets. The GPC supplementation was equally as effective in antioxidant potential as vitamin E. On the basis of these observations, we concluded that GPC could be a new source of antioxidant in animal nutrition.

Effects of dietary polyphenol-rich grape products on intestinal microflora and gut morphology in broiler chicks

Grapes have high amounts of phenolic compounds, which can modulate the gut activity as well as modify the structure and function of the gastrointestinal tract. The microbiological activity of avoparcin, grape pomace concentrate, and grape seed extract was evaluated in an in vitro study. An in vivo experiment was also conducted to study the effect of the inclusion of grape pomace concentrate and grape seed extract in the diet of broiler chicks on performance, intestinal microflora (by cultured and terminal restriction fragment length polymorphism methodology), and gut morphology at 21 d of age. Dietary treatments included an antibiotic-free diet (CON), a positive control (AVP; 50 mg/kg of avoparcin), and antibiotic-free diets containing grape pomace concentrate (GPC; 60 g/kg) or grape seed extract (GSE; 7.2 g/kg). Performance was not affected by dietary treatment except in the case of birds fed the GSE diet, which showed decreased weight gain. In the ileal content, birds fed CON and GSE diets had the highest populations of Lactobacillus. Compared with the CON diet, the AVP, GPC, and GSE diets increased the populations of Enterococcus and decreased the counts of Clostridium in the ileal content. In the cecal digesta, birds fed GPC and GSE diets had higher populations of Escherichia coli, Lactobacillus, Enterococcus, and Clostridium than birds in any other treatment group. Animals fed GPC and GSE diets showed a higher biodiversity degree than those fed control diets. The frequency of detection of several potential phenol-degrading bacteria as well as unidentified and uncultured organisms was increased in animals fed GPC and GSE diets. Birds fed the CON diet had longer villi and deeper crypt depth than birds in any other treatment group. The highest villi height:crypt depth ratio corresponded to birds fed GPC and AVP diets and the lowest to those fed CON and GSE diets. In conclusion, dietary polyphenol-rich grape products modify the gut morphology and intestinal microflora and increase the biodiversity degree of intestinal bacteria in broiler chicks.

Effect of enzyme supplementation of a diet based on barley, and autoclave treatment, on apparent digestibility, growth performance and gut morphology of broilers

An experiment was conducted with 270 chicks to investigate the autoclaving stability (0, 50, 70 or 90°C for 10 min) of a commercial poultry feed enzyme (β-glucanase) on the performance and gut morphology of birds fed a barley-based diet over 28 day period. Digestibilities of fibre, fat and starch were also determined on Days 12 and 28 of the experiment. The addition of the enzyme (heated and non-heated) significantly improved the performance (body weight and feed to gain ratio) and reduced the relative intestinal length (duodenum, jejunum, ileum and caeca) of the birds compared with those fed the non-supplemented diet (P < 0.05). There were no differences in the apparent digestibility of fibre among the different treatments and age of the birds. However, the ileal coefficients of fat and starch were reduced significantly (P < 0.001) in the birds fed the non-supplemented diet compared with those fed corn-soy and barley-based diets with enzymes heated and non-heated at both ages. Autoclaving treatment (70 and 90°C) improved significantly (P < 0.001) the performance of the birds fed the barley-based, enzyme-supplemented diet during the first week of age, without affecting the intestinal length and the digestibility of the nutrients studied. Histological observations on the small intestine epithelium of barley-fed birds indicated morphological changes in the jejunum compared with birds fed the corn-soy diet (shortening, thickening and atrophy of the villi and an increment in the number and size of globet cells). The addition of enzymes, heated or non-heated, to the barley diet improved these histological alterations. The enzyme was found to maintain its activity through conditioning temperatures, manifested by a positive effect on performance digestibility of nutrients and gut morphology.

Antioxidative effect of dietary grape pomace concentrate on lipid oxidation of chilled and long-term frozen stored chicken patties

Grape pomace concentrate (GPC) is a natural source of phenolic compounds with high antioxidant capacity. The effect of a diet containing GPC on lipid peroxidation levels (TBARS) and antioxidant capacity (ABTS method) of raw and cooked chicken breast meat patties stored in chilled conditions (4°C) for 0, 3, 6, 13 and 20days, and long-term frozen storage (6months) was investigated. Chickens were fed GPC at levels of 0, 30 and 60mg/kg from 3 to 6weeks of age. Dietary GPC did not affect chicken performance. Lipid oxidation (TBARS value) was significantly increased by the storage time (0-20days and 6months of storage, respectively) in raw and cooked samples. Dietary GPC significantly caused an inhibitory effect on lipid oxidation of raw and cooked breast chicken patties compared with samples obtained from birds fed the control diet at 20days and long-term frozen storage (6months). Radical scavenging capacity was significantly increased at 20days in cooked samples and significantly reduced at 6months of storage in raw and cooked samples. The higher concentration of dietary GPC increased the ABTS values only in the raw samples. These results indicated that dietary grape pomace concentrate could be effective in inhibiting lipid oxidation of chilled and long-term frozen stored chicken patties.

Changes in polyphenol and polysaccharide content of grape seed extract and grape pomace after enzymatic treatment

Grape seed extract and grape pomace are rich sources of polyphenols. The aim of this study was to evaluate the release of polyphenols, the solubilisation of carbohydrate, and the antioxidant capacity of these grape by-products after enzymatic reaction with carbohydrases (cellulolytic and pectinolytic activities) and tannase for 24h. The use of tannase in these by-products, and pectinase in grape pomace changed the galloylated form of catechin to its free form, releasing gallic acid and increasing the antioxidant activity. In grape pomace, cellulase treatment was not efficient for phenolic release and antioxidant activity improvement. The addition of carbohydrases to grape pomace, either alone or in combination, degraded the cell wall polysaccharides, increasing the content of monosaccharides. These results provide relevant data about the potential of pectinase, tannase and combinations of enzymes on the release of polyphenols and monosaccharides from grape by-products, improving the antioxidant capacity and the nutritional value.

Interaction of dietary high-oleic-acid sunflower hulls and different fat sources in broiler chickens

The effect of dietary fat sources (high-oleic-acid sunflower seeds, HOASS; palm oil, PO; and high-oleic-acid sunflower oil, HOASO) and high-oleic-acid sunflower hulls (HOAS hulls; 40 g/kg of diet) on performance, digestive organ size, fat digestibility, and fatty acid profile in abdominal fat and blood serum parameters was evaluated in chickens (from 1 to 21 d of age). Bird performance and digestive organ size were not affected by either dietary fat source or sunflower hull supplementation. Fat digestibility in birds fed diets enriched (HOASS and HOASO) in monounsaturated fatty acids (MUFA) was increased compared with those fed the PO diet. The addition of sunflower hulls did not modify fat digestibility. The fatty acids pattern of abdominal fat reflected the dietary fat profile. The greatest concentrations of C16:0 and C18:0 were found in birds fed PO diets. The C18:1n-9 content was increased in birds that received HOASS and HOASO diets compared with those fed PO diets. The greatest content of C18:2n-6 was observed in birds fed HOASS diets. The ratio of polyunsaturated fatty acid (PUFA) to MUFA was significantly increased in birds fed PO diets compared with those fed HOASS or HOASO diets. The addition of sunflower hulls to the diets resulted in a decrease of C18:2n-6 and PUFA concentrations and PUFA:MUFA ratio in abdominal fat. Dietary fat sources and sunflower hulls modify blood triglycerides and serum lipoproteins. A decrease in triglyceride concentrations was observed in birds fed HOASS diets compared with those fed PO and HOASO diets. The greatest concentrations of serum high density, very low density (VLDL), and low density lipoproteins were found in birds receiving HOASO, PO, and HOASS diets, respectively. The addition of sunflower hulls to the diets caused an increase of serum triglycerides and VLDL concentrations. The MUFA-enriched diets had lower triglyceride and VLDL concentrations than did diets rich in saturated fatty acids. However, the sunflower hull addition had the opposite effect.

Effect of dietary high-oleic acid sunflower seed, palm oil and vitamin E supplementation on broiler performance, fatty acid composition and oxidation susceptibility of meat

1. A study was conducted to evaluate the effect of inclusion of two fat sources: high-oleic acid sunflower seed (HOASS; 0, 50, 100, 150 and 200 g/kg diet) and palm oil (PO), and dietary supplementation of vitamin E (α-tocopheryl acetate, 200 mg/kg diet) on performance, fatty acid composition and susceptibility to oxidation of white and dark chicken meat during refrigerated storage. Female chicks (3 to 6 weeks) were given one of 5 diets containing 90 g/kg of added fat with increasing monounsaturated fatty acid (MUFA) content, adjusted by progressively replacing PO by HOASS. 2. Body weight gain and gain:food ratio of birds were depressed in diets containing the highest proportions of HOASS (150 and 200 g/kg). Relative abdominal fat was reduced in birds fed diets including HOASS, except in the diet containing 100 g HOASS/kg. The inclusion of α-tocopheryl acetate improved body weight gain and gain:food ratio. 3. According to the fatty acid profile of the diets, saturated and polyunsaturated fatty acid (SFA and PUFA, respectively) contents were significantly reduced and MUFA content was significantly increased in white and dark chicken meats when the saturated oil, PO, was replaced progressively by HOASS in the diet. The inclusion of α-tocopheryl acetate increased PUFA content in both meats. 4. After 4 and 7 d of refrigerated storage, white and dark meat samples obtained from birds fed on diets containing HOASS had significantly lower thiobarbituric acid reacting substance (TBARS) values than those derived from the PO diet. The addition of α-tocopheryl acetate significantly reduced the lipid oxidation in white and dark meat. 5. Overall, the results showed that increasing MUFA content of chicken meat by replacing dietary PO with HOASS (up to 100 g/kg) did not adversely affect broiler performance and reduced the susceptibility of meat to oxidation during refrigerated storage. Dietary α-tocopherol supplementation improved chicken performance and was effective in protecting lipid meat from oxidation.

Effects of dietary grape seed extract on growth performance, amino acid digestibility and plasma lipids and mineral content in broiler chicks.

Polyphenols are chemically and biologically active compounds. Grape seed extracts (GSEs) have been widely used as a human food supplement for health promotion and disease prevention. However, there is little information regarding its application in animal feeds. An experiment was conducted to investigate the effect of inclusion of GSE at 0.025, 0.25, 2.5 and 5.0 g/kg in a wheat soya bean control diet on growth performance, protein and amino acid (AA) digestibility and plasma lipid and mineral concentrations in broiler chickens at 21 days of age. Performance was not affected by dietary treatment except in the case of birds fed the diet with the highest GSE concentration, which showed a worsening of weight gain and feed conversion. Apparent ileal digestibility (AID) of protein was significantly reduced in the birds fed the highest concentration of GSE, which also had a reduction on the AID of arginine, histidine, phenylalanine, cystine, glutamic acid and proline compared with those fed control diet. The inclusion of graded concentration of GSE in the chicken diets caused a significant linear decrease in the concentrations of plasma copper, iron and zinc. Plasma cholesterol, triglycerides and lipoproteins (high-density lipoprotein, low-density lipoprotein and very-low-density lipoprotein) concentrations were not affected by dietary GSE. In conclusion, this study demonstrated that incorporation of GSE in chicken diets up to 2.5 g/kg had no adverse effect on growth performance or protein and AA digestibility. Feed conversion was reduced and growth rate was retarded, when chickens were fed 5 g/kg of GSE. This study also indicated that grape polyphenols reduce the free plasma minerals.

Nutritional value of raw and autoclaved kabuli and desi chickpeas ( Cicer arietinum L.) for growing chickens

1. Two experiments were carried out to determine the effect of inclusion of raw ( kabuli and desi ) and autoclaved ( desi ) chickpea seeds in wheat-based starter diets in chickens grown to 28 d of age on the performance, digestive organ sizes, nitrogen-corrected apparent metabolisable energy (AME n ), ileal apparent protein and starch digestibilities (APD and ASD) and intestinal α -amylase and trypsin activities. 2. In the first experiment, diets were formulated to contain 0, 150, 300 and 450 g/kg of raw kabuli chickpea seeds. Increasing the proportion of seed in the diet negatively influenced body weight gain, food intake and food efficiency. The relative weights of the pancreas, liver and gizzard and the relative lengths of duodenum, jejunum, ileum and caeca were increased significantly when the chickpea seeds were included in the diets. Correspondingly, APD, ASD, α -amylase and trypsin activities and AME n were reduced significantly when the chickpea seed was incorporated in the diets. 3. In the 2nd experiment, diets were formulated to contain 75 and 150 g/kg of raw and autoclaved desi chickpea seeds. Weight gain and food intake of the chicks given desi chickpea diets were significantly reduced compared with those fed on the control diet. Increasing the proportion of seed in the diet negatively influenced body weight gain, food intake and food efficiency. Moreover, a significant increment in the relative weights of liver and pancreas, and in the relative lengths of duodenum, ileum and caeca was observed when the concentration of chickpea seeds in the diets was increased. Feeding autoclaved seeds significantly increased the weight gains and the food intakes. However, food efficiency was not modified by the autoclaving. Relative weights of gizzard and liver and relative lengths of ileum were decreased significantly by the inclusion of autoclaved desi chickpea in the diet. 4. We concluded that the inclusion of kabuli (up to 450 g/kg) and desi (up to 150 g/kg) chickpea seeds produced a negative effect on the performance of the birds, and an increment in the relative weights and lengths of the digestive organs. In addition, the incorporation of kabuli chickpea produced a reduction of protein and starch digestibilities, α -amylase and trypsin activities, and AME n of food compared with the birds given the control diet. Autoclaved treatment of desi chickpea improved the performance of the birds.

Effects of citric acid and microbial phytase on amino acid digestibility in broiler chickens.

1. Two experiments with growing chickens were carried out to study the effects of the inclusion of a microbial phytase (Natuphos® 5000) and citric acid (CA) in maize–soybean-based diets on the performance and apparent ileal digestibility (AID) of crude protein (CP) and amino acids (AA). In both experiments the diets were formulated to contain the same amounts of energy and protein. 2. In the first experiment, data were analysed as a 2 × 2 factorial arrangement with two concentrations of available phosphorus (AP) from one day to 3 weeks of age (3·5 and 2·2 g/kg) and for 3 to 6 weeks (2·7 and 1·4 g/kg), and two inclusions of commercial phytase (0 and 500 FTU/kg) in each period. The AID of CP and dispensable and indispensable AA were not modified by the AP content of the diet. Addition of phytase improved the AID of CP and dispensable and indispensable AA only at low AP levels. 3. In the second experiment, data were analysed as a 3 × 2 factorial arrangement with three concentrations of citric acid (0, 20 and 50 g/kg) and two inclusions of commercial phytase (0 and 750 FTU/kg). Diets were formulated with deficient contents of AP (2·5 g/kg). Performance was not affected by commercial phytase addition. The addition of CA reduced the weight gain but did not modify the feed intake and gain:feed. In general, the AID of CP and dispensable and indispensable AA were not affected by CA addition. Commercial phytase increased the apparent ileal digestibility of crude protein but had no effect on AID of dispensable and indispensable AA. 4. In conclusion, the present work showed that microbial phytase enhanced AA digestibility in maize–soy-based diet only at very low AP concentrations, and that CA had no affect on the AID of CP and dispensable and indispensable AA. No synergism between CA and microbial phytase was detected.