C. Alzueta

Effects of inulin and enzyme complex, individually or in combination, on growth performance, intestinal microflora, cecal fermentation characteristics, and jejunal histomorphology in broiler chickens fed a wheat- and barley-based diet

A study was undertaken to examine the effects of inulin, alone or in combination with enzyme complex (primarily xylanase and beta-glucanase), on growth performance, ileal and cecal microflora, cecal short-chain fatty acids, and d-lactic acid and jejunal histomorphology of broiler chickens fed a wheat- and barley-based diet from 7 to 35 d of age. A total of 240 seven-day-old male Cobb broilers were allocated to 1 of 6 treatments, with 8 replicate pens per treatment and 5 birds per pen. The experiment consisted of a 3x2 factorial arrangement of the treatments with 3 concentrations of inulin (0, 10, or 20 g/kg of diet) and 2 concentrations of enzyme complex (0 or 100 mg/kg of diet). At the end of the experiment, 8 birds per treatment (one from each pen) were randomly chosen and slaughtered. Birds fed inulin-containing diets exhibited significantly (P=0.043) improved final BW gain. Dietary inulin had a positive and significant (P<0.002 to 0.009) effect on bifidobacteria and lactobacilli counts in both ileal and cecal contents and, to an extent, also altered the fermentation patterns in the ceca, increasing the concentration of n-butyric and d-lactic acids and the n-butyric acid:acetic acid ratio. Inulin inclusion had no effect on villus height and crypt depth or microvillus length, width, and density in the jejunum. Enzyme supplementation of the control diet and inulin-containing diets had no effect on many of the variables studied and only resulted in a decrease in crypt depth and an increase in villus height:crypt depth ratio in the jejunum.

Effect of inulin supplementation and dietary fat source on performance, blood serum metabolites, liver lipids, abdominal fat deposition, and tissue fatty acid composition in broiler chickens

A study was conducted to evaluate the effect of adding inulin to diets containing 2 different types of fat as energy sources on performance, blood serum metabolites, liver lipids, and fatty acids of abdominal adipose tissue and breast and thigh meat. A total of 240 one-day-old female broiler chicks were randomly allocated into 1 of 6 treatments with 8 replicates per treatment and 5 chicks per pen. The experiment consisted of a 3 x 2 factorial arrangement of treatments including 3 concentrations of inulin (0, 5, and 10 g/kg of diet) and 2 types of fat [palm oil (PO) and sunflower oil (SO)] at an inclusion rate of 90 g/kg of diet. The experimental period lasted from 1 to 34 d. Dietary fat type did not affect BW gain but impaired feed conversion (P < 0.001) in birds fed the PO diets compared with birds fed the SO diets. The diets containing PO increased abdominal fat deposition and serum lipid and glucose concentrations. Triacylglycerol contents in liver were higher in the birds fed PO diets. Dietary fat type also modified fatty acids of abdominal and i.m. fat, resulting in a higher concentration of C16:0 and C18:1n-9 and a lower concentration of C18:2n-6 in the birds fed PO diets. The addition of inulin to diets modified (P = 0.017) BW gain quadratically without affecting feed conversion. Dietary inulin decreased the total lipid concentration in liver (P = 0.003) and that of triacylglycerols and very low density lipoprotein cholesterol (up to 31%) in blood serum compared with the control groups. The polyunsaturated fatty acid:saturated fatty acid ratio increased in abdominal and i.m. fat when inulin was included in the SO-containing diets. The results from the current study suggest that the addition of inulin to broiler diets has a beneficial effect on blood serum lipids by decreasing triacylglyceride concentrations The results also support the use of inulin to increase the capacity of SO for enhancing polyunsaturated fatty acid:saturated fatty acid ratio of i.m. fat in broilers.

Effect of inclusion level of linseed on the nutrient utilisation of diets for growing broiler chickens

Abstract 1. Diets containing linseed at inclusions of 0, 80, 120 and 160 g/kg were evaluated for digestibility of nutrients and AME n content with male broiler chickens. 2. Increasing the concentration of linseed decreased the retention of nitrogen and the digestibility of amino acids, crude fat and fatty acids of diets. 3. Dietary AME n (MJ/kg) was also affected by the rate of inclusion of linseed, values decreasing from 14.39 to 12.49. 4. In general, a linear regression model explained the relationship between dietary linseed content and nutritive parameters. However, the quadratic response found for the digestibility of several amino acids and fatty acids indicated a non-additive change in their digestibility. 5. Viscosity of jejunal digesta was markedly increased by each increment of linseed in the diets. This is attributable to the presence of mucilage in linseed and it might explain many of the results obtained in this study.

Effect of whole and demucilaged linseed in broiler chicken diets on digesta viscosity, nutrient utilisation and intestinal microflora.

1. A study was undertaken to evaluate the effects of the inclusion of linseed or demucilaged linseed in the diet on the performance, fat and fatty acid digestibilities, metabolisability of gross energy and intestinal microflora. 2. The dietary inclusions were 80 and 160 g/kg for linseed and 160 g/kg for demucilaged linseed. Diets were given to chickens from 1 to 23 d of age. 3. Incorporation of linseed in the diet, particularly at 160 g/kg, depressed weight gain and food utilisation. Digestibility of fat and single fatty acids and dietary metabolisable energy were reduced. 4. Inclusion of linseed in the diet markedly increased the viscosity of ileal digesta. Microbial activity in the ileum and caeca was not greatly affected, but there was a significant increase in the number of lactobacilli. 5. The antinutritional effects caused by feeding linseed were partially overcome by substituting demucilaged linseed for linseed in the diet. 6. Results from the current study suggest that the viscous properties of mucilage are a major factor in the observed antinutritional effects of linseed through increasing intestinal viscosity. Such effects might also be mediated by the gut microflora.

Effects of faba bean tannins on the growth and histological structure of the intestinal tract and liver of chicks and rats

1. Diets containing a freeze-dried tannin extract from faba beans (Vicia faba L.) at concentrations of 0, 8 and 16 g/kg were fed to growing chicks and rats. 2. Chicks fed on the tannin-containing diets exhibited a high mortality and significant decreases in body-weight as well as lower food intakes and higher food intake:weight gain ratios (P < 0.01). In rats there was no mortality but the growth and food intake were adversely affected (P < 0.05). 3. Histological changes occurred in the ileal mucosa of chicks. Atrophy and shortening of villi with distortion of their architecture were observed. Similar histological disorders but less pronounced were also found in rats. 4. Histopathology of the liver of both chicks and rats showed an hydropic degeneration of hepatocytes, clearly more severe in the former than in the latter.

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.

Metabolisable energy value and digestibility of fat and fatty acids in linseed determined with growing broiler chickens

1. In the first experiment, the AME N of linseed was evaluated at rates of 40, 80, 160 and 240 g/kg in a basal diet with broiler chickens aged 28 d using the total collection method. 2. Increasing the concentration of linseed decreased the AME N of diet, from 11.78 to 8.75 MJ/kg DM, and AME N of linseed, from 16.64 to -2.96 MJ/kg DM. The negative values clearly indicated that linseed interacted with the other dietary ingredients and impaired their energy utilisation. 3. In the second experiment, a semipurified diet with graded addition of linseed (80, 120, 160 and 240 g/kg DM) was evaluated for crude fat and fatty acid apparent digestibilities. The coefficients decreased from 0.602 to 0.359 for crude fat and from 0.661 to 0.352 for individual fatty acids as the level of linseed increased. 4. In both experiments, a quadratic regression model explained the relationship between data better than the linear model. 5. The presence of mucilage and other antinutritional factors in linseed might explain the results obtained in this study.

Effect of inulin on growth performance, intestinal tract sizes, mineral retention and tibial bone mineralisation in broiler chickens

1. A 5-week feeding trial with 240 one-day-old male broiler chickens was conducted to investigate the responses of performance, intestinal tract measurements, relative apparent retention of minerals (Ca, Mg, Fe, Zn and Cu), and tibial bone measurements and mineral content (ash and Ca) to dietary graded levels of inulin. Treatments consisted of a maize–soybean meal control diet without or with supplemental antibiotic (flavomycin, 40 mg/kg diet) and 4 diets containing inulin at concentrations of 5, 10, 15 and 20 g/kg. 2. Growth performance of birds and morphological measurements of intestinal tract (duodenum, jejunum, ileum and caeca) showed no response to dietary levels of inulin as compared with the control diet and the control diet with flavomycin. 3. Dietary inulin improved the relative apparent retention of Ca, Zn and Cu (up to 18·4, 35·5 and 466%, respectively), did no affect that of Mg and impaired the retention of Fe. Differences among inulin treatments and control with flavomycin were significant only for Mg content. 4. Dietary inulin increased the concentration of ash and Ca in the tibiae. This effect was not reflected in the tibial bone morphology (weight, length and width). In conclusion, the results from the current study suggest that feeding inulin to broiler chickens may have a beneficial effect on bone quality.

Effects of inulin on growth performance, nutrient digestibility and metabolisable energy in broiler chickens.

1. A 35 d feeding trial with 480 d-old male broiler chickens (Cobb) was conducted to evaluate the effects of graded levels of inulin (0, 5, 10, 15 and 20 g/kg diet) in a maize-soybean meal based diet on growth performance, AMEN and apparent ileal digestibility (AID) of crude protein, amino acids, starch, crude fat and fatty acids. A commercial product (Inulina 95®) containing 914⋅0 g/kg of inulin and a degree of polymerisation (DP) ranging from DP 1–10 to DP 51–60 was used. 2. The performance of birds (feed intake, BW gain and feed to gain ratio) was not affected by the different dietary inclusions of inulin. 3. Dietary inulin significantly improved the AID coefficient of crude protein and crude fat. Also, there was a significant effect of inulin on the digestibility of most amino acids (10 out of 15) and major fatty acids (oleic and linoleic acids). The AID coefficient of starch and the AMEN content of diets were not affected by inulin inclusion. 4. In conclusion, the current study showed that inulin supplementation improved the digestibility of protein and fat in a maize-soybean meal based diet, but had no effect on the performance of broiler chickens.