Scielo RSS <![CDATA[Revista Brasileira de Zootecnia]]> vol. 48 num. lang. pt <![CDATA[SciELO Logo]]> <![CDATA[Influence of forage production area, concentrate supply, and workforce on productive results in milk production systems]]> ABSTRACT This study aimed to investigate the influence of forage production area, concentrate supply, and farm labor on characterization of milk production systems (MPS) and their productive results. Milk volume data provided in 2014 by 110 dairy farms located in the eastern region of Santa Catarina State, Brazil, were obtained from a dairy industry. Forty-four farms with different production levels were selected, in which interviews were carried out aiming to characterize the management practices related to forage production area, concentrate supply, and farm labor. A principal component analysis (PCA) was performed. Then, regressions were made between the principal components (PC) and indicator variables of productive response (annual milk production, milk production per area, milk production per cow, milk production per worker on farm, and number of cows per hectare). Finally, we performed a hierarchical agglomerative cluster analysis based on the PCA, followed by comparison of the means between clusters. Three PC were generated: indicator of scale and intensification, indicator of age of the manager and his experience on dairy farming, and indicator of specialization and permanent family labor available. The three PC were influencing the production results, especially PC1. It was possible to form five clusters: cluster 1, characterized by the highest value in PC1, showed the highest production results, followed by the cluster 2, with intermediate values in PC1; clusters 3, 4, and 5, characterized by lower values in PC1 and distinguished by PC2 and PC3, had the lowest productive results. Aspects related to forage production area, concentrate supply, and workforce are important for MPS characterization and have significant influence on productive results. <![CDATA[Oil blends with sesame oil in fish diets: oxidative stress status and fatty acid profiles of lambari]]> ABSTRACT The objective of this research was to evaluate the growth performance, oxidative stress, and fatty acid profiles of lambari (Astyanax altiparanae) fed diets containing different lipid sources: soybean oil, linseed oil, and freshwater fish residue oil combined or otherwise with sesame oil (SEO). The fish (mean weight 0.95±0.46 g; mean length 4.21±2.77 cm) were distributed into 24 cages (cage capacity: 0.70 m3; fish density: 276 individuals m−3) in six treatments and four replicates. After 80 days of feeding, they were weighed, and samples were collected for assay of catalase, glutathione reductase (GR), and lactate dehydrogenase (LDH) enzyme activities in muscle and analysis of the fatty acid profiles of polar and neutral fractions of whole eviscerated fish. The addition of SEO reduced docosahexaenoic acid (C22:6n-3, DHA) levels but increased the percentage of highly unsaturated n-3 fatty acids and the DHA: eiocosapentaenoic acid ratio, while reduced GR and LDH enzyme activities in muscle. Thus, certain blends of oils added to fish diets can improve the lipid profile of lambari and protect consumers against reactive oxygen species. <![CDATA[Multivariate analysis using morphometric and ultrasound information for selection of tilapia (<em>Oreochromis niloticus</em>) breeders]]> ABSTRACT This study evaluated morphometric and ultrasound information of tilapia (O. niloticus) breeders through multivariate analysis. We applied correlation, clustering, and principal component analysis to a dataset composed of information from 222 male and female breeders of the improved GIFT strain. The body weight, objective of the breeding program, showed a high positive correlation with most of the morphometric parameters. The formation of clusters indicated characteristics responsible for muscle composition and carcass weight. Some characteristics showed a high correlation, such as body weight and fillet weight (0.98 and 0.94 for females and males, respectively), and a high contribution to the explanation of data variability; of the total characteristics evaluated for females, two explained 75% data variability and four explained 72% for males. We concluded that it is possible to reduce the number of characteristics measured, as well as use information of average daily weight gain and body weight to select female and male breeders, respectively, to drive genetic gains favoring more productive generations. <![CDATA[Feeding rate and feeding frequency affect growth performance of common snook (<em>Centropomus undecimalis</em>) juveniles reared in the laboratory]]> ABSTRACT The effects of feeding rate and feeding frequency on the growth of laboratory-reared common snook (Centropomus undecimalis) were evaluated. Juveniles with mean±SD weight of 2.55±0.48 g and total length of 6.81±0.48 cm were divided into groups of 20 fish and reared in 30 polyethylene tanks of 50 L for 60 days. The experimental design was a 3 × 3 factorial with three feeding frequencies (F2, F4, and F6: two, four, and six daily meals, respectively), three feeding rates (R1, R2.5, and R4: 1.0, 2.5, and 4.0%/day of fish biomass, respectively), and three replicates, totaling nine treatments (F2R1, F2R2.5, F2R4; F4R1, F4R2.5, F4R4; F6R1, F6R2.5, and F6R4). The external control consisted of four meals a day offered to apparent satiety (F4S). Every 15 days, weight and length of all fish were measured to adjust the amount of feed offered. Water quality variables remained within adequate levels for this species. Feeding rate had a greater influence on performance than frequency. Survival, condition factor, and the initial and final coefficients of weight variation had no significant effect among treatments. Feeding frequency and rate directly influenced length and weight gains, feed efficiency, specific growth rate, and apparent feed conversion rate. For common snook juveniles weighing between 1 and 16 g, it is recommended to offer four to six daily meals at a feeding rate between 3.31 and 1.86% per day, which should decrease according to fish size. <![CDATA[Effect of stock density of cultured Amazon Apple Snail <em>Pomacea dolioides</em> (Gastropoda: Ampullariidae) in Brazil]]> ABSTRACT This study evaluated the biomass gain, specific growth rate, absolute weight gain, and survival rate of the gastropod Pomacea dolioides cultivated in different stocking densities. To perform the experiment, samples were collected in March and June 2015. A total of 40 adult specimens were collected in the Jauary neighborhood (03°08′19.9"S, 58°27′32.5"W), municipality of Itacoatiara, AM, Brazil. They were kept in the laboratory for breeding to obtain the young P. dolioides, which were distributed into tanks containing 4 L of water and an aeration system, in three densities: 2.5 animals/L, 5 animals/L, and 10 animals/L, and were fed fish ration (34% gross protein). The specimens were measured for shell length and weight every fifteen days. The survival rate did not differ between treatments 2.5 and 5 animals/L (100%) and 10 animals/L (95.83%). The density with the best cultivation results was 2.5 animals/L, being most effective for the parameters of growth, weight gain, specific growth rate, and percentage weight gain, when compared with the other treatments after 225 days of the experiment. For future cultivation of this species, a density of 2.5 animals/L should be used to improve handling performance. <![CDATA[Eucalyptus oil to mitigate heat stress in broilers]]> ABSTRACT The objective of this study was to evaluate performance, hematological parameters, leukocyte counts, and respiratory microbiota of broilers under heat stress receiving eucalyptus oil supplementation. Cobb broilers (n = 1200) were randomly distributed on the first day of life in a factorial arrangement with additional treatment (2 × 2 + 1) with two periods of oil administration via drinking water (daily, from 18 to 35 days of life) and two periods of oil administration via spray (daily, from 18 to 35 days of age) plus a control treatment, consisting of twelve replications, with 20 animals each. The birds were kept in a controlled environment with constant temperature at 32 °C to induce heat stress by infrared heaters. Eucalyptus oil was supplied by drinking water (1 L of oil to 4000 L of water) or by spray applications with a pump (1 L of oil to 200 L of water). Bird weight was recorded at 42 days of age, along with remaining feed, to determine weight gain, feed intake, and feed conversion. In addition, one blood sample from each bird repetition was collected for hematological and leucocytic evaluation. To assess respiratory microbiota, a tracheal flushing was performed for bacteria counts. There was no difference in performance, hematological parameters, and leukocyte counts, except hematocrit, which was lower in birds that received eucalyptus oil after 18 days of age. No significant differences were observed in the respiratory microbiota comparing oil-treated and -untreated groups. Although it was not possible to verify statistical difference, the birds that received eucalyptus oil via spray plus spray from 18 days old showed lower bacterial counts and absence of isolation of Gram negatives, while the control group was the one with the highest number of Gram negatives. Therefore, eucalyptus oil can be used for heat-stressed broilers without impairing their development. <![CDATA[Availability of betaine present in fine wheat bran in diets for growing pigs]]> ABSTRACT The objective of this paper was to investigate the availability of betaine present in fine wheat bran (FWB) in diets for growing pigs. We used thirty crossbred intact males, housed individually in metabolic cages and distributed in a randomized block design, with five treatments and six replicates. Blocks consisted of two periods of 15 days. Average initial body weights were 32.00±1.30 and 44.90±1.32 kg, in the first and second periods, respectively. Treatments were modified only at the level of methionine plus cysteine (Met+Cys) required and the Met+Cys sources, consisting of a negative control (NC), formulated with 80% of Met+Cys requirements, and four positive controls (PC): PCMet - NC supplemented with 1.2 g kg−1 of DL-methionine; PCBet - NC supplemented with 0.9 g kg−1 of anhydrous betaine; PCFWB - diet formulated with FWB; and PCFWB+Met - PCFWB supplemented with 1.0 g kg−1 of DL-methionine. No differences were observed on performance-related variables or on the digestibility coefficient of dry matter. Conversely, the digestibility coefficient of crude energy was lower when pigs were fed FWB and could be associated to the higher fiber content of FWB feeds. Digestible energy of feeds was higher for FWB diets, while the metabolizable energy of FWB diets did not differ from PCMet and PCBet. Nitrogen intake and apparent absorption were lower when pigs were fed FWB, but nitrogen retention, protein utilization, and biological value of the feed protein were the same among PC treatments, indicating that nitrogen from diets was used by pigs with the same efficiency, and is supported by no differences in performance-related variables. The FWB composition showed 12 g of betaine kg−1, which is available to maintain nitrogen retention and performance. <![CDATA[Organic minerals with different chemical characteristics in diets for Hy-Line White laying hens: performance, biometry of digestive organs, and bone quality]]> ABSTRACT Two trials were carried out to evaluate the effect of groups of organic minerals with different chemical characteristics on the performance, egg quality, biometry of digestive organs, and bone quality of laying hens in the first and second laying cycles. In the first cycle, 180 layers at 72 weeks were used in a completely randomized design (CRD) with four treatments and five replicates with nine birds each. In the second cycle, 216 layers at 94 weeks of age were used in a CRD with four treatments and six replicates with nine birds each. Birds were fed the following diets: treatment 1 - basal diet (inorganic minerals); treatment 2 - basal diet + amino acid chelated minerals (Cu, Fe, Mn, and Zn) + selenium yeast; treatment 3 - basal diet + mineral-amino acid complex (Mn, Zn, and Cu); and treatment 4 - basal diet + metal chelate (Mn, Zn, and Cu) + methionine hydroxy analogue. The following performance variables were evaluated: feed intake (g/bird/day), egg production (%), egg weight (g), egg mass (g/bird/day), conversion per mass (kg/kg), and conversion per dozen eggs (kg/dz). In the egg, the percentages of albumen, yolk, and shell; eggshell thickness (mm); and specific gravity (g/cm3) were determined. The relative weights (%) of the proventriculus, gizzard, liver, pancreas, and intestines were also measured. Lastly, in the tibiae, the weight (g), length (mm), resistance (kgf/cm2), deformity (mm), Seedor index (mg/mm), and mineral matter content (g/kg) were measured. The variables were not influenced by the groups of organic minerals used. Groups of organic minerals with different chemical characteristics can be used in layer diets without affecting their performance, egg quality, digestive organs, or bone quality. <![CDATA[Increased urinary losses in piglets fed diets containing high levels of glycerin]]> ABSTRACT This study evaluated the nutritional value of glycerin added to diets of weaned piglets and its effects on animal performance and urinary losses. Weaned piglets were individually housed in metabolic cages and fed diets in which a basal diet containing lactose (Gly0) was replaced by 50 (Gly50), 100 (Gly100), or 150 g kg−1 (Gly150) of glycerin; or a diet in which 100 g kg−1 of the lactose in the basal diet was replaced by glycerin (Gly100Lac0). Diets were offered for two periods of 12 days (phase I and phase II). Performance, nutrient digestibility, nitrogen retention (NR), and urinary production were measured. Digestible (DE) and metabolizable energy (ME) of glycerin were calculated using substitution method and compared to iso-nutritional diets formulated with or without glycerin. No significant differences on average daily gain, average daily feed intake, and feed conversion ratio were found. Glycerin inclusion caused a linear increase in urinary production. Piglets fed Gly100Lac0 diet had higher urinary production, compared with piglets fed Gly0. Glycerin had no significant effects on total tract apparent digestibility (TTAD) coefficients of dry matter (DM), crude protein, and gross energy (GE). Also, no significant effects were found in total tract apparent metabolizability (TTAM) coefficient of GE, NR coefficient, DE, ME, and fecal GE losses. Urinary production and GE in urine increased linearly and quadratically, respectively, with increased levels of glycerin in diets. The Gly100Lac0 diet resulted in lower DM TTAD and GE TTAM and higher GE losses in urine and feces compared with Gly0. The nutritional value of glycerin allows its inclusion at up to 100 g kg−1 in diets of weaned piglets without impairing animal performance and metabolism. Also, glycerin can replace 100 g kg−1 of lactose without impairing performance. <![CDATA[Enzyme complex at different levels in diets with enriched ingredients for commercial laying hens]]> ABSTRACT The objective of this study was to evaluate levels of inclusion of an enzyme complex (EC) in corn- and soybean meal-based diets for laying hens on the digestibility of nutrients and energy. A metabolism trial was conducted using 75 Dekalb Brown laying hens at 26 weeks of age, which were distributed into five treatments with five replicates in a completely randomized design. The ingredients used in the diets received an additional (enriched) 3% methionine, lysine, cysteine, threonine, tryptophan, and metabolizable energy and 33.3% phosphorus. Treatments consisted of diets including 0, 150, 200, 250, or 300‒1 EC. We determined apparent metabolizable energy (AME); nitrogen-corrected AME (AMEn); apparent metabolizability coefficients of dry matter (DMAM), crude protein (CPAM), gross energy (GEAM), and phosphorus (PAM); digestible crude protein (CPD); and intake, retention, and excretion of phosphorus. No effects of EC levels were detected on the metabolizable energy values or digestibility coefficients, except for CPAM, which showed a quadratic response (maximum coefficient at 89.0‒1EC). A quadratic effect was also observed for CPD (minimum at 115‒1 EC), P excretion (maximum at 173.2‒1 EC), and P retention (maximum at 122.4‒1 EC) when EC was used. The use of the EC in corn- and soybean meal-based diets for laying hens improves their ileal digestibility of protein and apparent digestibility of phosphorus. However, EC addition to the diets does not affect AME, AMEn, or their metabolizability coefficients.