Evaluation of sodium butyrate and nutrient concentration for broiler chickens.

The relation between nutrition and intestinal health is a subject with an increasing interest in research, as nutritionists need knowledge about how formulation affects different parameters in the gastrointestinal tract (GIT). That is why 4 trials were conducted to evaluate the effect of nutrient concentration and a feed additive (sodium butyrate protected with sodium salts of palm fatty acid distillates (PSB, Gustor N'RGY produced by Norel S.A., Spain, dosed at 1 kg/t), on performance, diet digestibility, intestinal morphology, volatile fatty acid concentration (VFA) in the GIT and intestinal microbiota of broiler chickens, when fed diets with different energy and amino acids concentration. Control diets, C, with the recommended metabolizable energy (ME) and ideal amino acid (AA) composition; Reduction 1, R1, C - 60 kcal ME and - 2.3% AA and Reduction 2, R2, C - 120 kcal ME and - 4.6% AA) based on different feed ingredients (Corn Soy [CS] and Wheat Barley Soy (WBS) were formulated. All trials lasted 42 d. In trials 2 and 4, the nutrient dilution decreased performance of the animals. In all trials, PSB improved animal performance (growth or FCR), despite the different situations. In trials 1 and 4, animals receiving R1 diets and PSB showed similar performance to those receiving C diets without PSB. PSB improved Gross Energy metabolizability (69.94 vs. 72.55; P: 0.02). Nutrient concentration affected histology results in T2 (ileum) and T3 (jejunum); PSB showed effects in T2 (jejunum, ileum) and in T3 (jejunum). In T1, PSB affected VFA in duodenum, jejunum, and ileum, changing the profile depending on diet nutrient concentration. PSB altered microbiology in caecum of animals in T2. It can be concluded that the dilution of ME and AA concentration of the diet impairs animal performance, influences intestinal microbiota and affects intestinal histology. PSB improves animal performance, increases gross energy metabolizability, steers intestinal microbiota and alters VFA concentrations in the intestine. The addition of PSB may help the animal to counteract the negative effects of diluted diets.

Growth curve and diet density affect eating motivation, behavior, and body composition of broiler breeders during rearing.

The aim of this work has been to assess the effect of diet density [control (CON) or 15% diluted (DIL)] and growth curve [recommended by the genetic line (RBW) or 15% heavier (HBW)] and their interaction on BW uniformity, feeding motivation, behavior, and body composition of broiler breeder pullets. A total of 3,000 one-day-old female breeders Ross 308, distributed in 20 pens, was randomly assigned to each treatment. Feed allowance was weekly adjusted to reach the desired BW. Feed was provided as pelleted (zero to 3 wk) and crumble (4 to 19 wk). Time eating was measured at 7, 11, and 19 weeks. A feeding rate test was performed after 11 weeks. Behavior was observed at 9 and 15 wk, by visual scan. At 6, 13, and 19 wk of age, one bird/pen was slaughtered for weighing different organs and analyzing the composition of empty whole bodies. Treatments did not affect BW uniformity; relative weights of the ovary, oviduct, or gizzard; or protein content of empty BW. Time eating varied with the growth curve at 19 wk (P < 0.05), HBW pullets spent 19 more min eating than RBW pullets. DIL led to 4 and 8 more min eating at 19 wk for pullets of RBW and HBW (P < 0.05), respectively. Pullets fed DIL consumed 30% (P < 0.05) less during the feeding rate test when kept on a restricted regimen, and they had lower compensatory energy intake after ad libitum feeding than those fed CON, indicating lower feeding motivation. Behavior was affected by the age and by the time of the d measured, but it did not change with the treatments. Birds spent most time pecking objects (50%), feeding (28%), and drinking (17%). Pullets fed DIL had 8% lower breast yield at different ages and higher empty digestive tracts at 6 weeks. Body composition varied with age; fat content increased from 12.7 to 15.9 to 19.8% for 6, 13, and 19 wk, respectively. The lowest body fat was observed for RBW pullets fed DIL (P = 0.003) at 19 weeks. Feeding DIL diets to HBW pullets could be done to increase the time spent eating and reduce their feeling of hunger without negative effects on body composition. However, its influence on behavior and BW uniformity was not proved.

Wheat starch digestion rate in broiler chickens is affected by cultivar but not by wheat crop nitrogen fertilisation.

1. A study was set up to investigate the influence of wheat cultivar and wheat crop nitrogen (N) fertilisation on starch (ST) digestion rate in broiler chickens. A total of 288 broiler chickens were used in a 3 x 2 factorial design with diets based on three varieties of wheat (Apache, Caphorn and Charger), each grown at two N application rates (40 and 170 kg of N/ha). 2. Starch digestion rate was determined by measuring the remaining starch and the mean retention time (MRT) in 4 segments of the small intestine (proximal and distal jejunum and proximal and distal ileum) and in excreta, using chromic oxide as a marker. 3. Varietal differences in starch content (714-746 g starch/kg DM) were smaller than differences caused by crop N fertilisation (705-755 g starch/kg DM). Nitrogen application increased wheat crude protein (CP) content from 94 to 130 g/kg DM. 4. The majority of the ST in all diets was digested by the time the digesta reached the distal ileum (average 0.84 in the distal jejunum and 0.96 in the proximal ileum). 5. Starch digestion differed among wheat cultivars in the proximal jejunum (from 0.43 to 0.57, P < 0.001). Afterwards no differences due to wheat cultivar or N fertilisation were found. 6. Starch digestion rate varied among wheat cultivars (from 2.45 to 3.28 h(-1), P < 0.001), but did not vary with N fertilisation, whereas dietary CP digestion rate was not affected by wheat cultivar or N fertilisation level. The digestion rate of ST was faster than that of CP (average 2.78 vs. 1.53 h(-1)). 7. The current study suggests that wheat cultivars can be classified on their rate of ST digestion independently of the N fertilisation applied to the crop during growth.

Wheat starch digestion rate affects broiler performance.

Two experiments were conducted to determine the differences in starch digestion rate (KDS) among wheats from different cultivars and origins and to verify if chickens would benefit from a certain digestion rate of starch. In the first experiment, 192 chickens (21 d) were assigned to 4 diets containing 55% of each wheat sample (3 cultivars, one of them from 2 origins). Starch and protein digestion were calculated from the remaining starch and protein in 4 segments of the small intestine and in excreta, using chromic oxide as a marker. Mean retention time was measured in each segment, which enabled calculations of digestion rates. In the second experiment, 2,600 chickens were assigned to 5 isoenergetic and isonitrogenous diets (with KDS from 1.80 to 2.56 h(-1)) and growth performance was determined (1 to 34 d). In 3 treatments, dietary starch was provided each by the wheat cultivars (same origin), whereas in the other 2 treatments, 25 and 50% of the wheat starch with the highest KDS was substituted by pea starch. Clostridium perfringens and Lactobacillus in the cecal chyme and glucose in the blood (glycemic index) were measured in broilers at d 19 and 25, respectively. Starch was gradually digested along the small intestine, mainly in the jejunum (48.5 and 80.4% at proximal and distal jejunum) where the largest differences among wheat samples were found. Starch digestion rate varied with origin (from 1.96 to 2.56 h(-1)) and cultivar (from 2.17 to 2.56 h(-1)). Crude protein digestion rate (average 2.21 h(-1)) was not affected by either cultivar or origin. Broiler growth and feed conversion ratio improved in a quadratic way with KDS. The maximum broiler performance was observed with KDS around 2.2 h(-1). Blood glucose response (glycemic index) was not affected by KDS; therefore, it cannot be used to predict broiler performance. In conclusion, the rate of starch digestion varies among wheats, depending on both genetic and environmental conditions of the grain, and affects broiler performance.

Effect of wheat cultivar and enzyme addition to broiler chicken diets on nutrient digestibility, performance, and apparent metabolizable energy content.

A total of 5,000 one-day-old male broiler chickens were assigned to 8 different treatments in a 4 x 2 factorial design. Four wheat cultivars (Amiro, Guadalupe, Isengrain, and Horzal) and 2 levels (0 or 1 kg/t of feed) of an enzyme cocktail (Avizyme 1300, xylanase, 2,500 U/kg and protease, 800 U/kg) were used. Nutritionally complete mash diets contained 65 and 70% of the test wheat for the starter and grower period, respectively. Test wheats were used in diets for broilers, and growth performance and AME contents were measured. Broiler performance was measured in 4,800 broilers allocated to floor pens with 75 birds each and fed from 1 to 42 d of age. Digestibilities and AME contents of diets were measured in 200 broilers from 6 to 27 d of age individually allocated to battery cages. Chromic oxide (Cr(2)O(3)) at an inclusion rate of 0.5% in the diet was used as an indigestible marker. Apparent metabolizable energy was corrected by zero N balance to obtain AME(n). Wheat cultivar strongly influenced animal performance during the starter period (1 to 21 d of age). During the grower period (21 to 42 d of age), only BW and daily feed intake were influenced by wheat cultivar. Differences in daily feed intake were associated with differences in AME(n) intake during the starter period, but not during the grower period. Nutrient digestibility was higher with the use of enzyme. Animal performance was not affected (i.e., wheat cultivar differences were not eliminated by using enzymes). During the grower period, significant interactions were detected with regard to nutrient digestibility and AME(n). Differences in AME(n) content of wheat could not be explained by digestible starch.

Nutritional evaluation of sunflower products for poultry as affected by the oil extraction process.

The nutritional value of sunflower seed (SFS) products was determined in two experiments using 180 adult Leghorn-type roosters (Hy-Line). In Experiment 1, press and solvent SFS oils were included in a basal diet at four graded levels (from 1.3 to 20%). Each diet was force-fed (30 g) to 10 roosters to determine their TMEn and true fat digestibility. Dietary TMEn and true digestible fat increased linearly (P < 0.0001) with oil inclusion. There were no differences in nutritional value between oils; their digestibility was 90%, which led to 8,385 +/- 39 kcal TME/kg DM. In Experiment 2, the effect of oil extraction on TMEn, true fat, and amino acid digestibility (TAAD) of SFS products was studied. Several products were derived from the oil extraction process: SFS, press extracted SFS (PESFS), and SFS meal (SFSM), as well as recombined products (mix of meal and oil) of SFS and PESFS, and were force-fed directly to 10 roosters each. Oil extraction produced a decrease (P < 0.0001) in true fat digestibility, TAAD, and TMEn (4,555, 2,591, and 1,754 +/- 59 kcal/kg DM for SFS, PESFS, and SFSM, respectively). Digestible fat content explained the difference between TME, of SFS and PESFS, whereas the difference between the TMEn of PESFS and SFSM was lower than expected. Recombined and original products had similar (P > 0.05) TMEn, despite solvent oil showing higher digestibility when released. Recombined SFS showed lower (P < 0.005) TAAD than original SFS (84.2 and 90.4%, respectively), indicating protein damage caused by heat and mechanical pressure. However, there were no differences, except for lysine, in TAAD between original and recombined PESFS (86.3 and 86.6%, respectively); both feeds showed higher (P < 0.05) TAAD than SFSM (83.9%), which indicates a positive effect of fat addition at this step.

Nutritional evaluation of sunflower seed and products derived from them. Effect of oil extraction.

1. Apparent MEn and oil digestibility of hulled sunflower seed (SFS) and the products derived from the oil extraction process: press extracted SFS (PESFS), sunflower seed meal (SFSM), and press and solvent oils (PO and SO) were determined with 198 cockerels. Recombined products (mix of meal and oil) were also evaluated to study the effect of the 2 consecutive oil extraction steps. Each foodstuff was included in a basal diet, according to the proportions resulting from processing, at 100, 200, and 300 g SFS/kg. 2. Dietary energy value and digestible fat content were linearly related to rate of inclusion of test ingredients. Extrapolation values for AMEn (MJ/kg DM) were: SFS, 16.20; PESFS, 9.46; SFSM, 7.62. A decreasing quadratic trend was also found in the AMEn of PESFS, with interpolation values ranging from 11.77 to 9.33 MJ/kg DM between 70 and 210 g/kg DM of inclusion. No differences were observed between PO and SO. The AMEn of of sunflower oil, calculated from its digestibility, was 33.70 MJ/kg DM. 3. The oil extraction process affected the nutritional value of sunflower products. Recombined materials showed greater values than original foodstuffs: R-SFS, 17.47; R-PESFS, 11.49 MJ/kg DM. The increase in oil digestibility (from 0.814 to 0.862 g/kg DM in SFS; from 0.778 to 0.892 in PESFS) accounted for most of the increase observed in AMEn values. 4. As the form in which oil is incorporated in diets (released or within SFS or PESFS) affects the utilisation of sunflower products, their nutritional value is less than maximal and should not be calculated from their ingredients. Solvent oil seems to be the less available fraction of sunflower oil within SFS as the effect of the 2nd extraction proved to be greater than that of the previous press extraction.

Composition of vitamin supplements in Spanish poultry diets.

1. The composition of 106 vitamin supplements used in about 85% of the Spanish poultry production diets were studied. Vitamin supplements were grouped by production classes and, for broilers and pullets, also by feeding periods. 2. Four vitamins (niacin, alpha-tocopherol, pantothenic acid, and riboflavin) comprised over 87% of the vitamin supplements by weight (choline excluded), whereas alpha-tocopherol and retinol represented from 51% to 60% of the total vitamin cost. 3. The highest and lowest vitamin supplementation rates were for broilers in the starter and withdrawal periods (106 and 44 mg/kg, respectively) and the mean values for breeders, pullets and layers were 104, 58, and 48 mg/kg, respectively. 4. Supplements with higher vitamin contents showed less variability in their composition. Retinol, cholecalciferol, riboflavin and pantothenic acid showed the lowest variability within supplements (6% to 36% CV), whereas alpha-tocopherol, menadione, thiamin and biotin showed the highest (40% to 224% CV). 5. Vitamin supplementation rates were compared with requirements, taking into account the dietary contribution. In general, vitamin fortification exceeded the NRC recommendations, using a high safety margin for some vitamins such as vitamin A (from 2.6 to 7.8) and for some poultry classes such as breeders (3.2).

Effect of storage time and dietary enzyme on the metabolizable energy and digesta viscosity of barley-based diets for poultry.

The effect of barley storage time and dietary enzyme addition on the energy value of barley-based broiler diets was studied in two experiments. A two-rowed winter barley (Beka cultivar) was stored at room temperature for 0, 3, 6, 16, and 32 wk after harvesting. At these dates, diets were formulated using 50% barley with and without the addition of a commercial beta-glucanase-based enzyme product. In Experiment 1, 320 Arbor Acres chickens (eight replicates of three 10-d-old birds and eight replicates of one 30-d-old bird, per treatment) were fed the experimental diets to determine the AMEn following a 2 x 2 x 5 (age by enzyme by barley storage time) factorial design. At the end of the metabolism trial, viscosity of the intestinal contents was determined in 30-d-old broilers. Total beta-glucan, nonstarch polysaccharides (NSP), in vitro viscosity, and endogenous enzyme activity of barley grain decreased with increasing storage time. Dietary AMEn increased with barley storage time (from 2,755 to 2,939 kcal/kg DM, P < 0.001, for 0 and 32 wk of storage, respectively), with enzyme addition (2,861 vs 2,919 kcal/kg DM, P < 0.003), and with the age of animals (2,826 and 2,958 kcal/kg DM for 10- and 30-d-old chickens, respectively, P < 0.001). Interactions of enzyme and age by barley storage time (P < 0.02 and P < 0.001, respectively) were also detected. These data indicate that the minimum time of barley storage before its inclusion in broiler feed depends on the animals' age (more than 6 wk for 10-d-old chickens and 3 wk for 30-d-old chickens), and that the use of enzymes allowed a reduction in the time of barley storage. Digesta viscosity decreased with barley storage time (P < 0.001), and with enzyme addition (P < 0.001), an interaction of storage time by enzyme addition was shown (P < 0.007). Digesta viscosity was also negatively related to the dietary AMEn content (r = -0.68, P < 0.01). In vitro barley viscosity explained 53 and 90% of the variation in gut viscosity produced by unsupplemented and enzyme supplemented diets, respectively. In Experiment 2, the same diets as Experiment 1 and the barley grain were intubated into 120 adult roosters (Hy-Line) to determine TMEn. Dietary and barley TMEn values were not affected by barley storage time or enzyme addition (3,237 and 3,037 kcal TMEn/kg DM for diets and barley, respectively).

Effect of chemical composition of sunflower seed meal on its true metabolizable energy and amino acid digestibility.

The effect of chemical composition of sunflower seed meal (SFSM) on TMEn and true amino acid digestibility (TAAD) was studied. In Experiment 1, the excretion pattern of three SFSM samples force-fed (30 g) to 10 adult cockerels (Hy-Line) each was followed for 84 h to determine the time interval for complete excretion of SFSM. Type of SFSM did not affect the excretion pattern of DM and energy (P=0.438, and P=0.189, respectively). Dry matter and energy excreted every 12 h decreased linear and quadratically (P < 0.001) with collection time. No differences were found from 48 h collection time on. So, an excreta collection period of 48 h was considered adequate for determining the TMEn of SFSM. In Experiment 2, 135 adult cockerels were force-fed to determine the TMEn of 11 samples of SFSM. Type of SFSM affected TMEn (P < 0.001), which ranged from 1,558 to 2,023 kcal/kg DM for SFSM of 31 to 42% CP, respectively. The TMEn was highly correlated (P < 0.001) to hemicellulose (r=-0.90), acid detergent lignin (r=-0.84), neutral detergent fiber (r=-0.82), and CP (r=0.77). Four prediction equations are proposed, the most practical being: TMEn (kcal/kg DM)=2,816.8 - 109.5 hemicellulose (%DM), RSD=70.2. Three out of the 11 samples of SFSM were selected for determining TAAD and the effect of endogenous amino acid correction. The methodology used was that of the TMEn assay, but one more estimation of amino acid endogenous excretion was made using a N-free diet with 85% cornstarch and 15% cellulose. Endogenous amino acid excretion was greater for roosters fed the N-free diet than those deprived of feed, resulting in a higher digestibility (from 0.7 to 2.7%, P < 0.05) only for six amino acids: threonine, valine, alanine, proline, and aspartic and glutamic acids. No interaction was detected (P=0.94) between type of SFSM and method of estimation of endogenous amino acid excretion. The TAAD of SFSM increased significantly (P < 0.001) with the CP content, total TAAD being 86, 88, and 89% for SFSM of 32, 35, and 37% CP, respectively. Attention should be paid when including high fiber-low protein SFSM in poultry diets to balance its lesser digestible amino acids contribution, mainly in lysine (from 0.77 to 1.06% for SFSM of 32 and 37% CP, respectively).

Energy evaluation of eight barley cultivars for poultry: effect of dietary enzyme addition.

Three experiments were conducted to study eight barley cultivars and the effect of enzyme addition on their energy value for poultry. In Experiment 1, the AMEn of a reference barley (Beka cultivar) was calculated by increasing barley concentrations (30, 40, 50, and 60%) that replaced a high protein basal diet. In Experiment 2, eight barley cultivars (four spring and four winter cultivars) replaced the reference barley in the diet with 50% barley inclusion. Two of the winter cultivars were two-rowed and two were six-rowed cultivars. A commercial enzyme was added to these diets to study the effect of enzyme addition. Diets were consumed ad libitum by 27 and 145 21-d-old Arbor Acres broiler chicks, in Experiments 1 and 2, respectively. In Experiment 3, 66 adult roosters were used to determine the TMEn of the eight cultivars used in Experiment 2. Dietary AMEn decreased linearly (P < 0.05) with increasing barley (Beka cultivar) inclusion. Beka barley AMEn was calculated by extrapolation of the linear regression equation be equal to 2,980 kcal/kg DM. Barley energy value was influenced by cultivar (P < 0.001); the spring cultivars showed greater energy value than the winter cultivars (2,963 vs 2,852 kcal AMEn/kg DM; 3,192 vs 2,929 kcal TMEn/kg DM). Two-rowed cultivars showed higher TMEn than six-rowed winter cultivars, although no differences were found for AMEn. The correlation between AMEn and TMEn values of barley was relatively low (r = 0.69); therefore, barley TMEn cannot be extrapolated to AMEn for young chicks. Enzyme addition produced an average increase of 220 kcal/kg DM in barley AMEn (P < 0.001); there was a significant (P < 0.10) interaction between barley cultivar and enzyme supplementation. The increment of barley AMEn caused by enzyme addition was partly explained (47%) by an increase in barley viscosity. This relationship implies that enzyme supplementation significantly improves the feeding value of high as compared to low viscosity barley samples, which involved a decrease in AMEn variation among cultivars for enzyme-supplemented barley. No relationship was found between AMEn of unsupplemented barley cultivars and their chemical composition. Instead, a relationship was detected for enzyme-supplemented barley; therefore two equations were proposed for predicting the AMEn of enzyme-supplemented barley to be used directly in diet formulation.