Scielo RSS <![CDATA[Revista Brasileira de Zootecnia]]> vol. 46 num. 6 lang. en <![CDATA[SciELO Logo]]> <![CDATA[Effect of dietary supplementation with butyrate and probiotic on the survival of Pacific white shrimp after challenge with <em>Vibrio alginolyticus</em>]]> ABSTRACT This study evaluated the performance, immunology, and survival of the Pacific white shrimp Litopenaeus vannamei to experimental challenge to Vibrio alginolyticus based on the use of the probiotic Lactobacillus plantarum and the combined use of probiotic and butyrate. Four different diets resulted from the addition of additives: butyrate, probiotic, butyrate + probiotic, and control (no additives). The attractiveness of the diets was assessed by the percentage of positive choices and rejections, using a dual-choice Y-maze format aquarium. The shrimps were fed during four weeks and performance parameters, intestinal microbiota, and immunological parameters were all evaluated. Subsequently, the shrimps were challenged with V. alginolyticus and after 48 h, survival and immunological parameters were evaluated. The results showed increased attractiveness and intake, but only with diets supplemented with sodium butyrate. However, other diets were not rejected. No difference in performance or immunological parameters was observed among the different diets. Also, among the treatments, no difference in Vibrio spp., or total heterotrophic bacteria counts, was found in the intestinal tract. However, the lactic acid bacteria count was higher in the intestinal tract of shrimps fed diets supplemented with probiotic. After bacterial challenge, shrimp fed all diets had a greater survival when compared with the control group. Lactobacillus plantarum and sodium butyrate increase the resistance of shrimp to infection with V. alginolyticus, but do so without affecting performance, immunological parameters, or Vibrio spp., and total heterotrophic bacteria counts in the intestinal tract. <![CDATA[Welfare of cattle kept in intensive silvopastoral systems: A case report]]> ABSTRACT The objective of this research was to evaluate the effect of three different intensive silvopastoral systems (ISPS) on cattle animal welfare (AW) in Colombia. The three ISPS differed in area, plant composition, and grazing periods as follows: ISPS1 - low plant diversity in paddocks of 1200 m2, with grazing period of 24 h; ISPS2 - middle plant diversity in paddocks of 600 m2, with grazing period of 12 h; and ISPS3 - high plant diversity in paddocks of 600 m2, with grazing period of 24 h. Animal welfare was assessed using a wide range of criteria, which were integrated using L-spline functions and Choquet integrals to generate overall values. It was found that AW was good in all ISPS; the highest scoring criteria was for food and water, with 99, 97, and 100 points from a maximum of 100 for ISPSs 1, 2, and 3, respectively. Comfort showed values of 100 for all three systems, but good health was the most problematic criteria of the AW features with scores of 25, 40, and 36 for ISPSs 1, 2, and 3, respectively. All three ISPS showed excellent scores for appropriate behavior (82, 88, and 89). The welfare problems shown here were not specific to the individual ISPS, but were common to all livestock systems in the region. Despite the differences in diversity of plants, size of paddocks, and grazing period among the three ISPSs tested, all of them provide cattle with sufficient resources and a diverse environment, ensuring a good state of welfare to them. <![CDATA[Chemical composition and fermentative parameters of heart of palm waste produced from Alexander Palm ensiled with chemical additives]]> ABSTRACT The objective of this study was to evaluate the chemical composition and the fermentative parameters of heart of palm waste produced from Alexander Palm, ensiled with chemical additives. Treatments consisted of silage of the sheath with or without calcium oxide. In the silage without calcium oxide, we evaluated the control silage (without additive) and the silage enriched with 5.0 g kg−1 urea (urea). In the silage with calcium oxide, we evaluated the silage enriched with 5.0 g kg−1 calcium oxide (control) and the silage enriched with 5.0 g kg−1 urea and 5.0 g kg−1 calcium oxide (urea). Experimental silos were distributed in a completely randomized design in a 2 × 2 factorial arrangement (inclusion or lack of lime × inclusion or lack of urea), with four replicates. Crude protein concentration was greater in the silages that received urea, whereas in the case of neutral detergent fiber and acid detergent fiber, the lowest levels were found in the control silage. Control silage had the lowest pH (3.75) and the silages that received lime displayed the lowest lactic acid content. Effluent losses were greater in the control silage and in the silage with lime (56.1 kg t−1 and 58.4 kg t−1, respectively). Silages prepared with waste from heart of palm production and enriched only with urea showed a better chemical composition and improved fermentation parameter estimates. We recommend the use of this waste only with additives that can improve the chemical characteristics of the forage. Without additives, unwanted fermentation processes may occur and compromise the quality of the silage. <![CDATA[Nutritive value of corn silage from intensive dairy farms in Brazil]]> ABSTRACT The objective of this research was to characterize the nutritive value of corn silage made on intensive dairy farms and demonstrate the nutritional variations between silages located at the top and at the center of a bunker silo. Thirty-two dairy farms were visited in four Brazilian states. One corn bunker silo of each farm was chosen and samples were collected from the top and center parts. The nutritive value, fermentation end-products, and microbial counts were assessed. The predicted milk was determined by Milk2006 spreadsheet. The mean, standard deviation, maximum, minimum, and 95% confidence interval of all data were calculated. The ash, neutral detergent fiber (NDF), starch, in vitro NDF, and dry matter (DM) digestibility data were compared with reference value. Both statistical procedures were performed through the PROC MEANS of SAS. The mean values found at the center for NDF, starch, total digestible nutrients (TDN-1x), and estimated milk were 503 g kg−1 DM, 308 g kg−1 DM, 583 g kg−1, and 1,124 kg t−1, respectively. The top silages presented a mean TDN-1x and predicted milk of 559 g kg−1 and 1046 kg t−1, respectively. For NDF digestibility and starch concentration, 53.1% and 62.5% of the center samples presented a value equal to or above the reference value (500 g kg−1 and 300 g kg−1 DM for NDF digestibility and starch concentration, respectively). Overall, the corn silage produced on intensive dairy farms in Brazil has satisfactory nutritive value, especially in terms of starch concentration. Some parameters, such as the concentration of fiber and its digestibility, should be improved. This study also shows that a silo may contain two different types of silage: top and center. This alerts nutritionists and farmers when feeding and sampling corn silage from bunker silos. <![CDATA[Effects of arginine and phytogenic additive supplementation on performance and health of brown-egg layers]]> ABSTRACT This study was performed to evaluate the effects of the association of different digestible arginine and phytogenic additive dietary levels on performance and health status of brown-egg layers. In this study, a total of 504 33-week-old Hisex Brown layers were distributed into a completely randomized experimental design to a 4 × 3 factorial arrangement (dietary digestible arginine levels: 880, 968, 1056, or 1144 mg/kg of feed × phytogenic additive levels: 0, 100, and 200 mg/kg of feed) with six replicate cages of seven birds per cage. The phytogenic additive was composed of extracts of Baccharis dracunculifolia (40%), Astragalus membranaceus lipopolysaccharides (20%), cinnamon, and grape seed (20%). Feed intake was reduced when diets containing 1056 mg of arginine were supplemented with 100 or 200 mg phytogenic additive per kg. Feed conversion ratio was improved when diets were supplemented with 100 mg of phytogenic additive or with 1056 mg of arginine per kg of feed. Egg mass was increased when diets were supplemented with 1056 mg arginine per kg of feed. Arginine supplementation quadratically increased albumen percentage and reduced yolk percentage. Higher arginine and phytogenic additive levels reduced heterophyl:lymphocyte ratio and blood uric acid, total cholesterol, very-low density lipoprotein, and triglyceride levels. Dietary supplementation of 100 mg of phytogenic additive associated with high arginine levels increased nitric oxide production by peritoneal macrophages and 1056 mg of arginine increased antibodies titers against Newcastle disease virus. Blood and intestinal malonaldehyde levels were reduced when 200 mg of the phytogenic additive was added. Dietary supplementation of 968 mg of arginine or 100 mg of a phytogenic additive (40% Baccharis dracunculifolia, 20% Astragalus membranaceus, 20% cinnamon, and 20% grape seed extracts) per kilogram of diet improves the feed conversion ratio and associated inclusion of 1144 mg of arginine and 100 mg of phytogenic additive per kilogram of diet improves immune responses and health status of brown-egg layers. <![CDATA[Performance, blood parameters, and carcass yield of broiler chickens supplemented with Mexican oregano oil]]> ABSTRACT The objective of the current study was to evaluate performance, blood parameters, and carcass yield of broilers supplemented with Mexican oregano oil. A total of 162 one-day-old broilers were randomly distributed into three dietary treatments: control diet (without oregano oil or antibiotic); control diet + 0.25 g kg−1 of oxytetracycline; and control diet + 0.4 g kg−1 of Mexican oregano oil. Treatment with organ oil had positive effects on body weight at 35 and 42 days. Feed intake was significantly different at 21 and at 1-42 days; control treatment presented the highest feed intake at 28 and 35 days, while treatment with oxytetracycline had the lowest feed intake from 21 to 42 days. Weekly body weight gain was different at 42 days, in which treatment with oregano oil was the highest and control the lowest. Feed efficiency rate was significantly different at 42 and at 1-42 days; treatment with oxytetracycline and treatment with oregano oil had the best values over control treatment. Blood parameters were found different among treatments, in which treatment with oregano oil was the highest in cholesterol and high-density lipoprotein at 42 days. Carcass and blood biometric variables were not different among treatments. The amount of 0.4 g kg−1 of Mexican oregano oil in diets improves high-density lipoprotein, body weight, and feed efficiency rate of broiler chickens. <![CDATA[Effects of increasing dietary concentrations of fish oil on lamb performance, ruminal fermentation, and leptin gene expression in perirenal fat]]> ABSTRACT The objective of this study was to evaluate the effects of four levels of fish oil on lamb performance, carcass yield, ruminal fermentation, and leptin gene expression in perirenal fat. Thirty-two lambs (24.10±2.15 kg, Katahdin × Pelibuey) were used in a completely randomized experimental design. The lambs were assigned to one of four dietary treatments (n = 8 lambs/treatment), expressed as g/kg DM basis: 0 fish oil and 300 corn; 10 fish oil and 250 corn; 20 fish oil and 205 corn; and 30 fish oil and 170 corn. The lambs were weighed on consecutive days at the beginning (days 0 and 1) and at the end (days 55 and 56) of the trial. Ruminal fluid samples were collected on day 56 to evaluate the ruminal fermentation pattern. The lambs were slaughtered on day 56; perirenal adipose tissue samples were collected and the carcass yields were recorded. Volatile fatty acids, ammonia N, and leptin mRNA expression were not affected by the dietary treatments. However, the dry matter intake, average daily gain, final body weight, and the hot carcass yield showed either increased linear or quadratic responses as the proportion of fish oil increased in the ration; the estimated optimal level obtained of fish oil levels for average daily gain was 11.2±0.21 g/kg and 12.8±4.67 g/kg for feed conversion. Additionally, feed efficiency and backfat thickness had an increment, showing quadratic response as the proportion of fish oil increased in the diet. Increasing the fish oil concentration in the diet does not affect leptin messenger ribonucleic acid expression. The lamb performance can be improved with 12 g/kg fish oil in diets of finishing lambs. <![CDATA[Discrimination ability of Santa Inês and crossbred Santa Inês × Dorper lamb heavy carcasses by the Brazilian and European classification systems]]> ABSTRACT The ability of discriminating carcass characteristics of different fat cover scores of heavy carcasses, according to the European (EUS) and Brazilian (BRS) classification systems, was assessed. Fifty-six lambs, weighing between 26.25 and 46.15 kg, of the Santa Inês and crossbred Santa Inês × Dorper genetic groups were evaluated. The level of adiposity was assessed through color photography of the carcasses after refrigeration according to the EUS and BRS. The carcasses were assigned to four groups by cluster analysis according to 25 variables, namely, cold carcass weight; muscle; bone; fat; and muscle:fat and fat:bone ratios of the carcass and cuts (hindquarter, shoulder, back); kidney, pelvic, and inguinal fat; and subcutaneous fat thickness. Of the four groups obtained by cluster analysis, the scores according to the different classification systems only statistically differed between groups 1 and 4. The BRS had a higher number of variables well correlated with the scores by assessors than the groups classified by the EUS. The BRS was better correlated with tissue composition. However, most variables were better correlated with backfat thickness than the score obtained through the classification systems. Better results were obtained regarding the prediction of carcass fat by the BRS using backfat thickness or cold carcass weight. The Brazilian lamb carcass classification system better predicts tissue composition and is the best method to discriminate intermediate-fat classes when associated with cold carcass weight. <![CDATA[Physiological responses of growing pigs to high ambient temperature and/or inflammatory challenges]]> ABSTRACT Global warming is one of the major environmental threats facing the world in the 21st century. This fact will have a significant impact on pig production due to its direct effects on welfare, health, and performance of pigs. Besides, the effects of high temperatures will presumably become more important over the next decades due to the development of pig production in developing countries mainly located in tropical and subtropical areas, where animals are often exposed to ambient temperatures above their thermal comfort zone. Furthermore, pigs reared in tropical areas are often confronted to sanitary challenges including poor hygiene conditions, lack of respect for sanitary rules, and pathogens. This results in the stimulation of the immune system and, as a consequence, in the production of pro-inflammatory cytokines and neuroendocrine adjustments that, in turn, usually have a negative impact on growth and feed efficiency. Although the effects of high ambient temperature and disease on pig physiology and performance have been well documented in literature, little is known about the associated effects of both factors. This understanding may contribute to a better quantification and comprehension of the physiological and metabolic disturbances occurring in practical conditions of pig production in tropical areas and, more generally, in many other geographic areas that will be influenced by the perspective of global warming. Therefore, the objective of this work is to provide an overview of recent research advances on the physiological responses of growing pigs during acclimation to high ambient temperature and on the potential effects of high ambient temperature on the ability of growing pigs to resist, cope with, or recover from an inflammatory challenge. <![CDATA[Future directions in breeding for disease resistance in aquaculture species]]> ABSTRACT Infectious disease is a major constraint for all species produced via aquaculture. The majority of farmed fish and shellfish production is based on stocks with limited or no selective breeding. Since disease resistance is almost universally heritable, there is huge potential to select for improved resistance to key diseases. This short review discusses the current methods of breeding more resistant aquaculture stocks, with success stories and current bottlenecks highlighted. The current implementation of genomic selection in breeding for disease resistance and routes to wider-scale implementation and improvement in aquaculture are discussed. Future directions are highlighted, including the potential of genome editing tools for mapping causative variation underlying disease resistance traits and for breeding aquaculture animals with enhanced resistance to disease.