Intake, nutrient apparent digestibility and ruminal constituents of sheep fed diets with canola, sunflower or castor oils

The objective in this experiment was to determine the effects of feeding diets with canola, sunflower or castor oils on intake, nutrient apparent digestibility and ruminal constituents of crossbred Dorper x Santa Ines sheep. Four rumen-cannulated animals of 90.2 +/- 11.4 kg average body weight were assigned to a 4 x 4 latin square. Animals remained individually in cages for the metabolism assay and were fed diets containing roughage at 500 g/kg and concentrate based on ground corn and soybean meal also at 500 g/kg. No oil was added to the control diet, whereas the others had canola, sunflower or castor oils at 30 g/kg (DM basis). There was no difference for the intake of DM and nutrients, except for ether extract, which was greater when animals received oil. The digestibility coefficients of dry matter, organic matter, crude protein, non-fiber carbohydrates and neutral detergent fiber were not changed; however, the addition of oil increased the ether extract digestibility. The values of total digestible nutrients (TDN, g/kg of DM), digestible energy (DE, Mcal/kg of DM), TDN intake and DE intake also did not change with the addition of lipids. Concerning the ruminal constituents, the addition of vegetable oils reduced the concentrations of acetate, butyrate and total short-chain fatty acids. Adding canola, sunflower or castor oils at 30 g/kg in diets with 500 g roughage/kg and 500 g concentrate/kg does not impair the intake or digestibility of nutrients in sheep, although it reduces the concentration of short-chain fatty acids in the rumen.

Growth, carcass characteristics, chemical composition and fatty acid profile of the longissimus dorsi muscle in goat kids fed diets with castor oil

The objective in this study was to determine growth, carcass characteristics, chemical composition and fatty acid profile of the longissimus dorsi of crossbred Boer x Saanen kids fed castor oil. Twenty-four kids (12 males and 12 females) were assigned in a randomized complete block design with two treatments and twelve replications. Blocks were defined according to weight, gender and initial age of animals for the evaluation of performance. The experimental treatments consisted of two diets containing 900 g concentrate/kg: a control diet (without addition of oil) and another containing castor oil at 30 g/kg (on a dry matter basis). After they reached an average body weight of 25 kg, males were slaughtered for the evaluation of carcass characteristics, chemical composition and fatty acid profile of the longissimus dorsi muscle. The addition of castor oil in the diet did not affect the intake of dry matter, crude protein and neutral detergent fiber; the average daily gain; and feed conversion, but increased the ether extract intake. No difference was observed for the carcass characteristics, chemical composition of the meat, concentration of C18:2 cis-9, trans-11 (CLA) and total concentration of saturated, monounsaturated and polyunsaturated fatty acids and their relations; however, there was increase in the concentrations of C18:2 trans-10, cis-12 (CLA) and C20:4 omega-6. The addition of castor oil to the diet of crossbred Boer x Saanen kids containing a high content of concentrate did not promote benefit to the characteristics evaluated.

Growth, body composition and hematology of juvenile pacu (Piaractus mesopotamicus) fed increasing levels of ractopamine

The effects of four levels of dietary ractopamine (RAC) on growth, body composition and hematology of pacu, Piaractus mesopotamicus juveniles (103.6+/-3.3g) were studied. Fish were housed into 12 circular tanks of 1 m(3) - 15 fish per tank - and fed for 60 days with practical diets supplemented with 0; 10; 20 or 40mg RAC per kg of diet, in a totally randomized design trial (n=3). Fish fed diets containing up to 40mg RAC/kg diet for 60 days did not have improved growth or body composition parameters. There were no significant differences in hematocrit, hemoglobin and mean corpuscular hemoglobin. Plasma glucose and triglycerides were significantly smaller in fish fed with RAC; however no significant differences between RAC levels were detected. The inclusion of up to 40mg RAC/kg of diet did not improve growth and body composition, but influenced some hematological and biochemical parameters of juvenile pacu.

Sources of organic trace minerals in diets for weaned piglets

One hundred and twenty six piglets from a commercial genetic strain weaned at 21 days of age (6.11 +/- 0.42 kg) were used to evaluate the effects of supplementation levels of organic sources of trace minerals in the diets of weaned piglets on performance, occurrence of diarrhea, excretion of copper and zinc in the feces, and hematological parameters. A completely randomized block design was adopted, composed of six treatments (diets containing 100% of inorganic trace minerals premix at 3.00 kg/T; diets containing 0, 25, 50, 75 or 100% of organic trace minerals premix, equivalent to 0; 0.75; 1.50; 2.25 or 3.00 kg/T, respectively), seven replicates and three animals per plot. During the experimental period (from 21 to 63 days of age), the increasing levels of organic trace minerals premix in the diets determined a quadratic effect on daily weight gain (DWG), feed conversion (FC), percentage of hematocrit (Ht), hemoglobin (Hb), mean corpuscular hemoglobin (MCH), mean corpuscular volume (MCV), platelets (Pt), and a linear increase of Cu and Zn concentrations in feces. The comparison of means between the treatment with inorganic trace minerals premix and the other treatments showed that piglets fed diets without trace minerals premix had lower values of DWG, Ht, Hb, MCH, MCV, Pt and the worst FC value of piglets fed diets containing 25% of organic trace minerals premix presented lower values of Ht and Hb, in comparison with those fed diets with 100% of inorganic trace minerals premix. Inorganic trace minerals premix can be substituted by organic trace minerals premix at a lower level of inclusion in diets for weaned piglets.

Prediction of culture performance of juvenile Litopenaeus vannamei by in vitro (pH-stat) degree of feed protein hydrolysis with species-specific enzymes

Rapid in vitro methods for measuring digestibility may be useful in analysing aqua feeds if the extent and limits of their application are clearly defined. The pH-stat protein digestibility routine with shrimp hepatopancreas enzymes was previously related to apparent protein digestibility with juvenile Litopenaeus vannamei fed diets containing different protein ingredients. The potential of the method to predict culture performance of shrimp fed six commercial feeds (T3, T4, T5, T6, T7 and T8) with 350 g kg(-1) declared crude-protein content was assessed. The consistency of results obtained using hepatopancreas enzyme extracts from either pond or clear water-raised shrimp was further verified in terms of reproducibility and possible diet history effects upon in vitro outputs. Shrimps were previously acclimated and then maintained over 56 days (initial mean weight 3.28 g) on each diet in 500-L tanks at 114 ind m(-2), clear water closed system with continuous renewal and mechanical filtering (50 mu m), with four replicates per treatment. Feeds were offered four times daily (six days a week) delivered in trays at feeding rates ranging from 4.0% to 7.0% of stocked shrimp biomass. Feed was accessible to shrimp 4 h daily for 1-h feeding period after which uneaten feed was recovered. Growth and survival were determined every 14 days from a sample of 16 individuals per tank. Water quality was monitored daily (pH, temperature and salinity) and managed by water back flushing filter cleaning every 7-10 days. Feeds were analysed for crude protein, gross energy, amino acids and pepsin digestibility. In vitro pH-stat degree of protein hydrolysis (DH%) was determined for each feed using hepatopancreas enzyme extracts from experimental (clear water) or pond-raised shrimp. Feeds resulted in significant differences in shrimp performance (P < 0.05) as seen by the differences in growth rates (0.56-0.98 g week(-1)), final weight and feed conversion ratio (FCR). Shrimp performance and in vitro DH% with pond-raised shrimp enzymes showed significant correlation (P < 0.05) for yield (R-2 = 0.72), growth rates (R-2 = 0.72-0.80) and FCR (R-2 = -0.67). Other feed attributes (protein : energy ratio, amino acids, true protein, non-protein nitrogen contents and in vitro pepsin digestibility) showed none or limited correlation with shrimp culture performance. Additional correlations were found between growth rates and methionine (R-2 = 0.73), FCR and histidine (R-2 = -0.60), and DH% and methionine or methionine+cystine feed contents (R-2 = 0.67-0.92). pH-stat assays with shrimp enzymes generated reproducible DH% results with either pond (CV <= 6.5%) or clear water (CV <= 8.5%) hepatopancreas enzyme sources. Moreover, correlations between shrimp growth rates and feed DH% were significant regardless of the enzyme origin (pond or clear water-raised shrimp) and showed consistent R-2 values. Results suggest the feasibility of using standardized hepatopancreas enzyme extracts for in vitro protein digestibility.

Digestible tryptophan:lysine ratio for laying hens

The objective of this study was to evaluate the requirement of digestible tryptophan for white laying hens in the production stage fed diets of different digestible tryptophan: digestible lysine ratios, as well as animal performance and histological alterations in their reproductive and digestive systems. A total of 280 white laying hens at 29 weeks of age were distributed in a completely randomized design with five treatments and seven replications with eight birds in each. The treatments consisted of a base feed, formulated with corn, soybean meal and corn gluten meal, and supplemented with the synthetic amino acids L-lysine, DL-methionine, L-threonine, L-isoleucine, L-arginine, and L-valine, so as to meet the nutritional requirements for laying hens, except for digestible tryptophan. The basal diet was supplemented with 0.00; 0.017; 0.035; 0.052; and 0.069 g/kg of L-tryptophan in substitution for corn starch with the objective of reaching the levels of 0.151; 0.167; 0.183; 0.199; and 0.215 g/kg of digestible tryptophan in the feed. For the ratio between digestible amino acids and lysine, the recommendation of Brazilian Tables for Poultry and Swine was followed, except for the digestible tryptophan: digestible lysine ratios, which were 19, 21, 23, 25 and 27 for each treatment. The variation in the digestible tryptophan: digestible lysine ratio promoted changes in performance and in the histological characteristics, improving the results. The digestible tryptophan: digestible lysine ratio of 24.5% in the feed of white laying hens in production stage promotes better animal performance and histological results.

Effects of feeding a multivalent polyclonal antibody preparation on feedlot performance, carcass characteristics, rumenitis, and blood gas profile in Bos indicus biotype yearling bulls

The objective of this study was to evaluate effects of feeding monensin (MON) or a multivalent polyclonal antibody preparation (PAP) against several rumen microorganisms on feedlot performance, carcass characteristics, blood gas profile, and rumenitis of Bos indicus biotype (BT) yearling bulls. The study was designed as a completely randomized design with a 3 x 2 factorial arrangement, replicated 4 times, in which 32 yearling bulls of each of 3 BT evaluated (3-way-cross, TC; Canchim, CC; and Nellore, NE) were fed diets containing either MON at 300 mg.d(-1) or PAP at 10 mL.d(-1) across 3 different periods. No significant (P > 0.10) feed additive (FA) main effects were observed for any of the feedlot performance variables and carcass characteristics with the exception of dressing percentage. Yearling bulls receiving PAP had a decreased (P = 0.047) dressing percentage when compared with yearling bulls receiving MON. Significant (P < 0.05) BT main effects were observed for all feedlot performance variables and carcass characteristics with the exception of kidney-pelvic fat expressed in kilograms (P = 0.49) and LM lipids content (P = 0.45). Crossbred yearling bulls (TC and CC) had greater (P < 0.001) ADG, DMI in kilograms, DMI as % of BW, and improved (P = 0.001) G: F when compared with NE yearling bulls. A tendency (P = 0.072) for a FA main effect was observed for rumenitis scores, in which yearling bulls receiving PAP had lesser rumenitis scores than those receiving MON. When the data were disposed as frequency percentage, 55.6% and 45.7% of the rumens from yearling bulls fed PAP and MON were scored between 0 and 1, respectively (0 = no lesions, 10 = severe lesions). Likewise, a significant BT main effect was observed (P = 0.008), where NE yearling bulls had greater rumenitis scores than those of crossbred yearling bulls (TC and CC). No signifi cant FA main effects were observed (P > 0.10) for any of the fatty acids measured in the subcutaneous adipose tissue, with the exception that yearling bulls receiving MON had greater (P < 0.05) concentrations of palmitic acid (16: 0), margaric acid (17: 0), docosapentaenoic acid (22: 5), and docosahexaenoic acid (22: 6) than those yearling bulls receiving PAP. Feeding PAP tended to decrease incidence of rumen lesions and led to similar feedlot performance compared with feeding MON. Thus, PAP is a new technology that presents a possible alternative for ionophores.

Metabolic changes in ruminant calves fed cation-anion diets with different proportions of roughage and concentrate

Two experiments were carried out with twenty-four male weaned Holstein calves to verify the influence of different dietary cation-anion concentrate and roughage proportions on calves metabolism. In the first experiment, calves were fed rations with -100, +200 and +400 mEq cation-anion balance/kg of dry matter, containing 60% of roughage and 40% of concentrate. In the second experiment, calves (117.6±20.8 kg average weight) received rations with similar dietary cation-anion balance but in diets of 40% roughage and 60% concentrate. As the dietary cation-anion balance became more positive, there was a quadratic response of blood pH in both diets with 60 and 40% roughage. A linear increase following increased dietary cation-anion balance was observed on bicarbonate concentration, carbon dioxide tension, carbon dioxide partial pressure and urine pH on both experiments, while anion gap decreased linearly. Blood urea nitrogen and base excess increased quadratically according to increased dietary cation-anion balance on 60% roughage, whereas those same parameters showed a linear increase on 40% roughage. Growing ruminant metabolism both in cationic and anionic diets was modified when the roughage:concentrate ratio was altered.

Effects of flavomycin on ruminal fermentation, In situ degradability and In vivo digestibility in bovine fed sugarcane diets

Problem statement: The aim of the present study was to characterize and differentiate the effects of addition of flavomycin or monensin on ruminal fermentation and degradability as well as on total digestibility in bovine. Approach: Twelve non-pregnant and non-lactating cows (736 kg of BW) were randomly assigned to three treatments: control, flavomycin (20 mg animal-1 day-1) and monensin (300 mg animal-1 day-1). The trial lasted 21 days. The last 10 days were used for external marker administration (15 g of chromic oxide animal-1 day-1). The last 5 days of the trial were used for feces collection and evaluation of corn grain, soybean meal or sugarcane ruminal degradability and the 21st day was used for ruminal fluid sampling. Results: Monensin increased 27.2%, on average, propionate molar proportion at 0, 4, 6, 8, 10 and 12 h after feeding, compared to control and flavomycin groups. When compared to control, flavomycin reduced the degradation rate of soybean meal CP in 31.0%, decreasing the effective degradability when passage rates of 5 and 8% h-1 were used. Dry matter intake, pH, total Short Chain Fatty Acids (tSCFA) or ammoniacal Nitrogen (NH3-N) concentration were not influenced by the addition of either antibiotics. Effective degradability of sugarcane NDF was not influenced by the use of either antibiotic; neither were the TDN nor the digestibility of DM, CP, EE, NFE, ADF, NDF, GE or starch of the diet. Conclusion/Recommendations: In the present study, it was possible to show the beneficial effects of monensin but not of flavomycin, on rumen fermentation

Effect of the inclusion of fish residue oils in diets on the fatty acid profile of muscles of males and females lambari (Astyanax altiparanae)

This study evaluated the effects of two lipids sources of fish residue (tilapia and salmon) compared with a vegetable oil source (soybean oil) on the fatty acid profiles of male and female lambari. This experiment was developed in a completely randomized experimental design in a 3 x 2 factorial arrangement, totaling 6 treatments resulting from the combination of the three experimental diets for both sexes, with four replications for each treatment. This study involved 120 male (2.58 +/- 0.13 g) and 72 female lambari (4.00 +/- 0.09 g), fed the experimental diets twice a day until apparent satiation for a period of 60 days. Oleic, linoleic, palmitic and stearic fatty acids were found at higher concentrations in all experimental oils and diets, as well in the muscle of male and female lambari. The low amounts of arachidonic, eicosapentaenoic and docosahexaenoic acids in the experimental diets and subsequent greater concentrations in muscle tissue, suggested that lambari are able to desaturate and elongate the chain of fatty acids with 18 carbons. The fish of both sexes that received the diet with soybean oil showed high levels of n-6 fatty acids, especially of C18: 2n-6 and low levels of eicosapentaenoic and docosahexaenoic acids. The diet with salmon residue oil promoted higher levels of fatty acids of the n-3 series and resulted in the best n-3/n-6 ratio in the muscle of male and female lambari. The oils from fish residues can be a substitute for traditional fish oil and its use in the lambari diets does not impair its growth.

Fatty acid composition of the longissimus dorsi muscle in crossbred steers fed different sources of fatty acids

The objective of this study was to evaluate the fatty acid composition of the longissimus dorsi muscle in carcasses of 3/4 Bos taurus taurus 1/4 Bos taurus indicus steers fed different sources of fatty acids. Thirty-six steers aged 14 months, with a mean live weight of 320 kg, were fed the following diets for 96 days:1) control diet, containing no supplemental fat source; 2) CaSFA, diet containing 50 g calcium salts of fatty acids per kg total dry matter; 3) CS diet, containing 210 g cottonseed per kg total dry matter. The fatty acid composition of the longissimus dorsi muscle was determined by gas chromatography. No difference in slaughter weight, carcass weight, backfat thickness, or longissimus dorsi muscle area was observed between animals receiving the diets CaSFA and CS. Animals consuming the two fat-supplemented diets presented higher concentrations of oleic (C18:1), palmitic (C16:0) and stearic (C18:0) acids, corresponding to an average 80.76% of total fatty acids, and higher concentrations of vaccenic acid (C18:1 t11) in the muscle when compared with the control group. Supplementation of the diet of feedlot crossbred steers with CaSFA or cottonseed did not promote significant alterations in the lipid composition of the longissimus dorsi muscle.

Protein diets promote the maturation of oocytes and spawning of Piaractus mesopotamicus kept in cages

The objective of this study was to evaluate the effects of balanced diets on the maturation of oocytes and the reproductive performance of P. mesopotamicus in cages. A completely random design with 224 fish in 16 cages measuring 5 m(3) was employed for this purpose. The treatments consisted of diets containing 18, 24, 30, and 36% crude protein (CP) provided ad libitum. The external and internal morphological characteristics of the specimens were examined, as well as: the position of the germinal vesicle, the distribution of oocyte diameters, the fertilization and hatching rates, the number of oocytes released, the total number of oocytes, the remaining weight and total weight of the ovaries, the gonadosomatic index, the condition factor (K), and the histology of the oocytes and ovaries post-spawning and during ovarian regression. The diameters of the oocytes collected before the first hormonal application displayed a unimodal distribution for the lowest protein content and a polymodal distribution for the other treatments. A similar situation was seen during spawning. The lowest fertilization and hatching rates were found as a consequence of the treatment with 30% CP (P < 0.05). The greatest hatching rate occurred in the females fed 18% CP. The greatest total oocyte weight was found in the specimens that received between 30 and 36% CP. The lowest K index was found in the females fed 36% CP. In conclusion, a diet containing 18% CP satisfies the reproductive requirements of females adapted to this system.

Metabolizable energy values of diets supplemented with xylanase determined with laying hens

The objective of this study was to evaluate the effect of the supplementation of xylanase in diets with reduced energy level on the apparent metabolizable energy corrected for nitrogen, determined with laying hens at 14, 36, 60 and 80 weeks of age. Four digestibility trials were conducted, using 80 Hy-line W36 laying hens aged 14, 36, 60 and 80 weeks of age. Birds were distributed in a completely randomized design in 2 x 2 factorial arrangement (energy level x inclusion of xylanase), totaling four treatments with 10 replicates of two birds each. Treatments were: positive control (balanced diet for their age); positive control + xylanase; negative control (diet with reduction of 100 kcal/kg in the level of metabolizable energy); and negative control + xylanase. Xylanase, produced by microorganism Trichoderma reesei, was added to the diets at 100 g/t (16,000 BXU/kg) for diets fed at 14 weeks and 75 g/t for diets of 36, 60 and 80 weeks (12,000 BXU/kg). The data obtained were subjected to analysis of variance at 5% probability. Supplementation of xylanase promoted higher values for AME (apparent metabolizable energy) and AME(n) (apparent metabolizable energy corrected for nitrogen) determined with 80-week-old laying hens, subjected to diet with energy level according to the nutritional requirements for their age. Supplementation of xylanase increases the matabolizability coefficient of the dietary crude protein and improves the nitrogen retention of laying hens at 14 weeks. In addition, xylanase associated with adequate levels of dietary energy promotes higher values for AME and AME(n) determined with laying hens at 80 weeks of age.

Bioelectrical impedance analysis and anthropometry for the determination of body composition in rats: effects of high-fat and high-sucrose diets

Objective The aim of the present study was to determine the impedance of Wistar rats treated with high-fat and high-sucrose diets and correlate their biochemical and anthropometric parameters with chemical analysis of the carcass. Methods Twenty-four male Wistar rats were fed a standard (AIN-93), high-fat (50% fat) or high-sucrose (59% of sucrose) diet for 4 weeks. Abdominal and thoracic circumference and body length were measured. Bioelectrical impedance analysis was used to determine resistance and reactance. Final body composition was determined by chemical analysis. Results Higher fat intake led to a high percentage of liver fat and cholesterol and low total body water in the High-Fat group, but these changes in the biochemical profile were not reflected by the anthropometric measurements or bioelectrical impedance analysis variables. Anthropometric and bioelectrical impedance analysis changes were not observed in the High-Sucrose group. However, a positive association was found between body fat and three anthropometric variables: body mass index, Lee index and abdominal circumference. Conclusion Bioelectrical impedance analysis did not prove to be sensitive for detecting changes in body composition, but body mass index, Lee index and abdominal circumference can be used for estimating the body composition of rats.

Addition of increasing doses of ricinoleic acid from castor oil (Ricinus communis L.) in diets of Nellore steers in feedlots

The aim of this study was to evaluate the performance and blood parameters of feedlot Nellore cattle fed increasing doses of ricinoleic acid (RA) in the diet. Ninety-six Nellore steers divided into 12 groups of 8 animals were used. The animals were randomly assigned to four treatments: 0, 1, 2, or 4 g of RA/animal/day, with three replicates per treatment. The experimental period consisted of 84 days divided into three 28-day periods preceded by three step-up diets. A quadratic effect was found for average daily gain and final body weight, as well as for leukocyte and lymphocyte counts, and for urea and blood urea nitrogen. A linear effect was observed for albumin, alkaline phosphatase, and gamma glutamyl transferase. The inclusion of 2 g of RA daily improved the performance of feedlot Nellore steers.