Zootechnical Indices Research Articles

Production strategies for controlling greenhouse gas emissions in grass-fed beef production systems

Looking at pasture-based beef cattle production systems, there needs to be more pasture management and low zootechnical indexes, which culminate in low productivity and environmental impact. In this sense, cattle farming has been labeled as harmful to the environment due to the emission of gases that can contribute to the excessive increase in the greenhouse effect. These gases are methane, nitrous oxide, and carbon dioxide, which come from ruminal fermentation, manure fermentation, and biomass management. The objective was to simulate eight scenarios: the first occurred in areas of degradation and desertification of pastures induced by livestock farming, the second occurred with the recovery of degraded pasture areas, the third occurred with the improvement of pasture management, the fourth occurred with the implementation of integrated production systems, the fifth occurred with the improvement in diet quality, the sixth occurred with the association of supplementation strategies for grazing cattle with fattening in confinement, the seventh occurred with the reduction in the feeding cycle production of beef cattle and the eighth occurred with the intensification of land use. It is concluded that the adoption of more intensive production systems proves to be more efficient, both productively and environmentally, by reducing the emission of greenhouse gases and improving zootechnical indices, guaranteeing the supply of animal protein in the face of growing demand globally.

Effect of sex and birth weight on the performance, microbiome, immune response and colostrum intake of piglets

The objective of this study was to evaluate the effect of sex and birth weight classes (BWC) on the colostrum intake, performance, permanence in the production system, immune response and microbiome of piglets in the farrowing and nursery phases. A factorial design was used with two sex categories (female and male) and three BWC (low - 0.8 to 1.1 kg; medium - 1.101 to 1.4 kg; and high - 1.401 to 1.7 kg). A total of 757 piglets in the farrowing phase and 228 piglets in nursery phase were used. Serum glucose concentration at birth and 24 hours, colostrum intake, performance parameters, removal rates, mortality, medication, and serum concentrations of immunoglobulin G (IgG), interleukin 10 (IL-10) and tumor necrosis factor alpha (TNF-α) on the 4th day after weaning, and fecal microbiome on the 6th day of nursery were evaluated. The serum glucose levels were not changed (P > 0.05). Piglets with high birth weight ingested more colostrum (P < 0.001). Low birth weight piglets (P = 0.077) and males (P = 0.027) had a higher removal rate and mortality. A higher percentage of females with high birth weight required medication (P < 0.001). The body weights of piglets at all weighings were higher for those with high birth weight (P < 0.001). The daily weight gain and feed intake during the nursery phase were affected by the BWC (P < 0.001). Low birth weight piglets had a lower concentration of TNF-α (P = 0.009), and there was no difference in IL-10 concentration (P > 0.05). Males tended to have higher serum IgG concentrations (P = 0.067). Medium- and high-weight piglets, as well as males, showed a higher abundance of pathogenic bacterial species (Fusobacterium mortiferum, Campylobacter jejuni, Clostridium neonatale and Ruminococcus torques). In conclusion, females had a higher rate of permanence in the production system and a fecal microbiome with a lower abundance of pathogenic bacteria, and low birth weight piglets had lower colostrum intake with reduced zootechnical indices.

Influence of the Glutaraldehyde-based and Quaternary Ammonium Compounds Based Aerosol Disinfectant on Some of the Physiological and Zootechnical Indices in Broiler Chickens

Introduction. A huge number of disinfectants are used for aerosol disinfection of poultry premises, most of them are recommended for preventive or terminal disinfection carried out in the absence of poultry. At the same time, some products available to veterinary services are recommended for concurrent disinfection and are used in the presence of poultry, although, not all of them meet the requirements on composition, purpose and mode of use. The one of interest is a glutaraldehyde-based and quaternary ammonium compounds (QAC) based disinfectant, which has already been investigated in the scientific sources, however the influence of this agent on the physiological and zootechnical status of poultry treated therewith has not been fully studied. The aim of this research is to study the physiological status and productive qualities of the broiler chickens exposed to direct aerosol treatment with the glutaraldehydeand QAD based disinfectant.Materials and Methods. The research was conducted from October to November 2019 in the industrial poultry farm settings in a large flock of broiler chickens of the Cobb 500 cross, divided into two groups — experimental and control one. In the experimental poultry house, on the 10th day after putting the broiler chickens in the house, a preventive aerosol disinfection was carried out by means of the Nebulo cold fogger in the presence of poultry. A 0.5% solution of glutaraldehydeand QAD based disinfectant was used in a dosage of 5 ml per 1 m3 (the maximum permissible concentration exceeding the recommended one). In the control poultry house the aerosol disinfection was not carried out. The biochemical tests of blood serum (alanine aminotransferase (ALT), aspartate transaminase (AST), total bilirubin, total protein, creatinine, blood urea, blood uric acid) were made using a biochemical analyser. The zootechnical indices were also studied (livability, mortality, average daily gain, feed and water consumption during the full growing life cycle, feed conversion ratio).Results. The time history of the blood serum biochemical indices showed that the use of the glutaraldehydeand QAD based aerosol disinfectant in the specified above dosage in the presence of broiler chickens did not cause a negative, toxic effect on chickens’ metabolic indicators — all changes fluctuated slightly within the physiological norm. The zootechnical monitoring data have revealed the positive effect of the aerosol disinfection on the growth and maturing of chickens, enhancement of the livestock livability and poultry average daily gain due to the decrease of microbial burden on the growing organisms of chickens. The broiler chickens livability during the entire growing period in the experimental group was 0.84% higher than in the control group. Also, the average daily gain by the end of the growing period in the experimental group was 1.52% higher than in the control group, and the average liveweight of one bird was 2 137.7 g (experimental group) and 2 111.1 g (control group). At the same time, the feed costs in the experimental group were 0.11% less than in the control group.Discussion and Conclusion. It was found that the use of a glutaraldehydeand QAD based aerosol disinfectant, even in the maximum permissible concentration in the presence of poultry, not only didn’t have a negative effect on the physiological and zootechnical status of the broiler chickens, but, on the contrary, fostered creation of the more comfortable conditions for their keeping and growing. The obtained research results allow us to confidently recommend this method of aerosol disinfection to be used in the animal and poultry keeping premises.

Adaptability of commercial probiotics to biofloc system: Influences on autochthonal bacterial community, water quality and growth performance of shrimp (Litopenaeus vannamei)

This study aimed to investigate the adaptability of commercial probiotics to the biofloc system, as well as the influence on bacterial community, water quality and aquatic animal growth. Two biofloc systems nursing Litopenaeus vannamei postlarvae for 28 days were designed, the control (cBFT) and pBFT with addition of commercial probiotics (containing Bacillus, Clostridium, Enterococcus, Lactobacillus and Rhodopseudomonas). Results showed that at the end of the experiment, only the absolute abundance and the proportion of Bacillus contained in commercial probiotics (2.1 ± 0.8 × 105 genome copies mL−1 and 0.12 ± 0.03%) significantly increased in pBFT compared to those in cBFT (1.7 ± 0.8 × 104 genome copies mL−1 and 0.03 ± 0.02%), respectively (P < 0.05). Absolute abundances and proportions of several autochthonal bacterial genera (i.g., Acinetobacter, Anaerospora, Arthrobacter, Devosia, Luteolibacter, Marivita and Mycobacterium) also significantly elevated in pBFT (P < 0.05). Total suspended solids (TSS) and turbidity (415.2 ± 79.6 mg L−1 and 379.0 ± 86.4 NTU) were significantly higher in pBFT than both parameters in cBFT (118.1 ± 23.9 mg L−1 and 109.4 ± 44.3 NTU), respectively (P < 0.05). Whereas, zootechnical indices (except survival rate) were significantly lower in pBFT than those in cBFT, respectively (P < 0.05). The integrated impact model of commercial probiotics explained 57.9%–77.1% variations of shrimp growth performance, and showed that commercial probiotics as well as some autochthonal bacteria positively correlated with turbidity which in turn negatively correlated with zootechnical indices (P < 0.05). The findings suggested that added probiotics (especially Bacillus) induced changes on the autochthonal bacterial community, leading to changes of water quality which consequently resulted in the depression of growth performance of shrimp.

Retracted: Sugarcane bagasse ameliorates zootechnical performances and expression of growth- immune-related, and antioxidant genes of Litopenaeus vannamei larvae in the biofloc technology

The role of sugarcane bagasse (SCB) as a cheap carbohydrate (CHO) source was evaluated in L. vannamei larvae on the zootechnical indices and the countenance of growth, immune and antioxident genes in the liver and muscle tissues. The experiment includes two treatments, the control which feeds a commercial diet and the SCB treatment. It continued for 45 days in outside ponds in ternary (each supplied with six hundred shrimp larvae). The results revealed that both growth and survival rates of SCB treatment were significantly improved (P < 0.05) when versus to the basal. The hepatic (H) and muscular (M) genes expression increased considerably in the SCB treatment (P ≤ 0.05) versus control. The SCB treatment was the highest in all mRNA transcripts of studied immune-related genes. The expression of antioxidant genes superoxide destmutase (SOD) and glutathione peroxidase (GPx) in both H and M were increased significantly in SCB treatment relative to the control. Generally, the results highlight the importance of inclusion SCB in a zero water exchange system without an artificial diet ameliorates both zootechnical and immunity in L. vannamei.

Integration agriculture-livestock and production “Bull Harvest”

Within agribusiness there has been a lot of debate on the topic of intensification and sustainability within agricultural practices, the current scenario of pasture livestock is seen as challenging due to the low quality of pastures and consequently low quality indices, on the other hand agricultural practices have increasingly evolved in productivity, but with criticism of environmental care. With this in mind, integration practices have a positive result that adds greater production with pasture recovery in addition to physical-chemical and microbiological improvements related to agricultural practices. The main challenge for the rancher is the off-season period, when there is low availability and quality of grass, which favors a peculiar quality of a longer cycle and greater risk, so integration practices are a strategy that was developed to overcome these challenges promoting gains in critical periods. Zootechnical indices such as higher batch rate are possible productivity and productivity gains with the practice area of ​​nutrient cycling and soil protection are more profitable and productivity. The work brings positive results cited in the literature show the efficient use of integration practices related to peculiarities and agricultural practices.

Manejo de bezerras bubalinas

ABSTRACT One of the main stages in bubalinoculture is breeding calves, because this phase is defined by the quality of the animals that will be the future property matrices. The breeding phase extends from birth to weaning, and is delicate and precise; consequently, attending to characteristics of extreme importance in dairy farming activity such as behavioral and health aspects will aid these animals to express all of their genetic potential. Since this life phase of the animal does not generate immediate economic return to the producer, it ends up not receiving the necessary attention, contributing to low zootechnical indices and high production costs. Adopting adequate management practices is essential for the productive development of the animal that will guarantee the future good productivity of the farm. In view of the above, the objective of this study is to present the management of buffalo calves through a literature review, emphasizing that proper feeding, correct management and disease prevention are fundamental to ensuring the well-being and health of calves. These factors, together with a clean and safe environment, can maximize the productive potential of these animals. It is therefore essential that producers are well-informed and prepared to properly care for these animals during this crucial phase of their lives.

A simple and low-cost environmental enrichment program improves the welfare of Calomys callosus, a species that adapts to animal facilities.

An environmental enrichment protocol is essential for testing experimental models because it upholds animal welfare, aligns with ethical principles in animal experimentation, and reduces the number of animals needed. Calomys callosus, a South American rodent from the Cricetidae family, is bred in rodent animal facilities for its ease of handling, longevity, prolificacy, and effectively mimicking diseases like Toxoplasmosis, Leishmaniasis, Chagas, and Schistosomiasis. There are no reports on environmental enrichments for this species or their impact on reproductive parameters. This study aimed to analyze the influence of the Environmental Enrichment Program (EEP) on the reproductive and zootechnical performance of C. callosus kept in the Rodents Animal Facilities Complex of Universidade Federal de Uberlândia (UFU). Two experimental groups were established: with environmental enrichment EE+ and without environmental enrichment EE-. The materials used in the experimental design were changed weekly and alternated between dietary, occupational, physical/cognitive, and non-enrichment items. After the inclusion of the EEP, an improvement in the reproductive indices of C. callosus was identified in the EE+ group. These improvements included increased female precocity, a decreased interbirth interval, and a higher number of pairs producing more offspring. The postpartum zootechnical indices were also better, such as the number of animals born alive, improved weaning rates, and a reduced average number of deaths from birth to weaning. After the inclusion of the EEP, the general health status of C. callosus improved, reducing cases of non-infectious lumbar alopecia. Therefore, EEP allows C. callosus to express natural reproductive behaviors and improves parental care.

Can in vitro embryo production be estimated from semen variables in Senepol breed by using artificial intelligence?

Thoroughly analyzing the sperm and exploring the information obtained using artificial intelligence (AI) could be the key to improving fertility estimation. Artificial neural networks have already been applied to calculate zootechnical indices in animals and predict fertility in humans. This method of estimating the results of reproductive biotechnologies, such as in vitro embryo production (IVEP) in cattle, could be valuable for livestock production. This study was developed to model IVEP estimates in Senepol animals based on various sperm attributes, through retrospective data from 290 IVEP routines performed using 38 commercial doses of semen from Senepol bulls. All sperm samples that had undergone the same procedure during sperm selection for in vitro fertilization were evaluated using a computer-assisted sperm analysis (CASA) system to define sperm subpopulations. Sperm morphology was also analyzed in a wet preparation, and the integrity of the plasma and acrosomal membranes, mitochondrial potential, oxidative status, and chromatin resistance were evaluated using flow cytometry. A previous study identified three sperm subpopulations in such samples and the information used in tandem with other sperm quality variables to perform an AI analysis. AI analysis generated models that estimated IVEP based on the season, donor, percentage of viable oocytes, and 18 other sperm predictor variables. The accuracy of the results obtained for the three best AI models for predicting the IVEP was 90.7, 75.3, and 79.6%, respectively. Therefore, applying this AI technique would enable the estimation of high or low embryo production for individual bulls based on the sperm analysis information.

Modeling the growth of Pacific white shrimp (Litopenaeus vannamei) using the new Bayesian hierarchical approach based on correcting bias caused by incomplete or limited data

The revenue, costs, and profit of an aquaculture farm are based on the weight of animal protein sold. Thus, there is a relationship between the economic and zootechnical indexes to the growth model of animals in a production system. The growth modeling of cultivated organisms can be used as a production management tool, allowing estimates of anticipated size at harvest, waste outputs, as well as nutrient and feed requirements, helping in decision-making in the face of Aquaculture 4.0. It is important to emphasize that recent research has indicated the possible underestimation of parameters in nonlinear growth models due to the characteristic of incomplete or limited data in aquaculture. Therefore, the objective of this research was to model the growth of Pacific white shrimp (Litopenaeus vannamei) in an industrial-scale shrimp farm in northeastern Brazil. Based on the Bayesian methodology for correcting this bias, six nonlinear hierarchical growth models were evaluated in this research (Morgan-Mercer-Flodin, Michaelis–Menten, Weibull, von Bertalanffy, Gompertz, and logistic growth equation) and fitted to real data from a shrimp farm in northeastern Brazil. The model was validated based on the predictive capacity (accuracy) to forecasting shrimp growth at different hierarchical levels. Finally, for one of the main expected results, a sensitivity analysis was performed to compare different treatments according to the new approach. The Weibull growth equation stands out as the best among all those studied (WAIC = 2661.3, LOO-IC = 2705.2). Although it presented a poor fit for the hierarchical population level, good predictions were realized at the pond level and at the production cycle level. The dataset was split into fit and homologation subsets for a model validation analysis which showed an accuracy of 95.76% and 85.71% at the pond and production cycle levels respectively. The proposed method detected subtle differences between production cycles, which would be imperceptible if analyzed using the zootechnical indices usually practiced in shrimp farms. The new approach can contribute to improving products, processes, and decision-making in aquaculture management.

Economic viability in the integrated crop-livestock system with nitrogen fertilization system and sward canopy heights

Integrated crop-livestock systems (ICLS) are complex production strategies whose main components are soil, plant, and animal. Several studies addressed the interaction among them and conclude on the technical feasibility of these systems, but few studies assess their economic feasibility. The objective of this work was to analyze the economic feasibility of an ICLS, in which nitrogen was applied on the crop phase or onto the pasture phase, combined with two grazing intensities. The study was carried out on a private farm in the municipality of Abelardo Luz—SC, between October 2012 and April 2018. The experimental design was randomized blocks with three replications. The treatments were arranged in a 2x2 factorial scheme, with two sward heights (high and low) and two times of N-fertilization application, or on the cool-season pasture tillering phase either onto cash crop (200 kg of N ha−1 in a single dose). Crop implementation and maintenance costs were surveyed, followed by crop and livestock production calculations, zootechnical indices, and the revenue of each phase (pasture or grain crop) for the entire system. The cash flow analysis was carried out, generating economic indicators of the three dimensions of the expanded multi-index methodology (MMA) for the system and the treatments. In this study, pasture management with low sward canopy height provided the highest net gains per hectare and per hectare/year, regardless of the nitrogen application time. The use of the ICLS is economically viable, regardless of grazing intensities and nitrogen application times.

Doenças periodontais e desgaste dentário em rebanhos ovinos no Estado de Goiás, Brasil

ABSTRACT: Dental and periodontal affections consist of health concerns of great importance in sheep flocks, as they affect the health and welfare of animals and represent one of the main causes of premature slaughter. Studies on the occurrence of these conditions in sheep are scarce in Brazil. The present study aimed to evaluate the prevalence of periodontal diseases and tooth wear in sheep flocks in the State of Goiás. For this, a clinical oral examination was conducted on 325 sheep from seven farms in six municipalities of the State. Periodontal lesions, characterized by gingival recession in at least one incisor tooth, were observed in 48.3% (157/325) of the sheep, while in cheek teeth it occurred in 13.2% (43/325) of the evaluated sheep. Dental wear on cheek teeth was identified in 69.2% (255/325) of the sheep, and 10.7% (35/325) of the ovines showed dental wear on incisor teeth. Sheep older than 36 months had an increase in the frequency of tooth wear. A total of 171 (52.62%) out of the 325 examined sheep had signs of bleeding on probing, which is compatible with gingivitis, and 69 (40.36%) were older than 36 months. Thirty-eight (11.69%) out of the 325 evaluated ovines had gingivitis in all teeth, among which 21 (55.26%) were older than 36 months. Logistic regression analysis allowed the observation that age was associated with the occurrence of gingivitis. Less frequent changes such as periodontal pockets and loss of at least one tooth were also observed in 4.9% (16/325) and 17.8% (58/325) of the sheep, respectively. It indicates that the presence of periodontal diseases and tooth wear is a common occurrence in the evaluated flocks. Therefore, there is a need to include the oral health of sheep in the routine of the farm as an essential preventive measure to improve the quality of life, animal welfare, and zootechnical indices.

Effects of a monocomponent protease from Bacillus licheniformis on broiler performance, digestibility, and carcass yield

Two experiments were carried out to evaluate the effects of protease addition to the diet of broilers at a higher level (1× or 2×) than the nutritional value proposed for the enzyme. The first experiment, 1280 day-old chicks (Cobb500®) were randomly allocated (randomized block design, 2×2+1 factorial arrangement), five treatments, eight replicates containing 32 birds/replicate. Treatments consisted: control diet without protease (CD); CD + 1× nutritional value of the enzyme (CDM1); CD + 2× nutritional value of the enzyme (CDM2); CDM1 + protease; and CDM2 + protease. The experimental period was 42 days. The mean weight (AFW), feed intake (FI), weight gain (WG), feed conversion, and carcass yield were evaluated. Significant differences were observed for AFW, WG, FI, abdominal fat yield, and feet percentage in the carcass. In the second experiment, 120 Cobb500® chicks at 14 days of age were allotted in a completely randomized design, 2×2+1 factorial arrangement, five treatments, six replicates with four birds/replicate. The treatments were consistent with the first experiment. Significant improvements in the nitrogen balance were observed for the broilers that received protease. The use of the enzyme tested is recommended with the recommended nutritional matrix, improving the zootechnical indices of broilers.

Safety and growth-promoting potential of repeated administration of sodium salicylate to broilers

Antimicrobial growth promoters (AGPs) have been banned from animal husbandry owing to their association with the occurrence of bacterial resistance. Although the mechanism of action of AGP is still unknown, it is believed to be related to an anti-inflammatory action in the gastrointestinal tract. In this context, the aim of the present study was to establish if supplementation of broiler feed with the non-steroidal anti-inflammatory sodium salicylate (SS) induces adverse effects related to this class of drug and to evaluate the potentiality of SS in improving the zootechnical indices of broilers. One-day-old Cobb 500 male chicks were divided into four groups (12 per group) and treated over a period of 42 days with non-supplemented feed (control group) or with feed to which doses of 2.5, 5.0, or 10.0 mg of SS/kg BW were added daily. Feed intake and BW were assessed and haematological, biochemical, and histopathological alterations were evaluated throughout the experiment. Whereas no statistical differences in food intake or BW were detected between the groups, a 5.8% increase in total BW gain was observed in broilers treated with 10 mg of SS/kg BW. In addition, the highest dose of SS studied generated the lowest total feed conversion rate over the experimental period in comparison with all other SS treatment groups. Haematological and biochemical evaluations did not reveal any altered parameters that could be related to the adverse effects of SS. No renal or hepatic alterations were detected in the histopathological study of tissue collected on day 42, and no lesions or ulcerations were observed in the gastrointestinal tract. We conclude that daily doses of SS in the range of 2.5–10 mg/kg BW can be added safely to broiler feed for 42 days, and that this non-steroidal anti-inflammatory drug is promising for future studies of its use as a growth-promoting agent.

Strategic diagnosis of a property specialized in breeding, rearing and finishing beef cattle in the southern region of Piauí

This study aimed to perform a strategic diagnosis on a property specialized in breeding, rearing and finishing beef cattle in the southern region of Piauí. It was conducted at Agropecuária Alvorada, located in the countryside, municipality of Bom Jesus, PI, Brazil. The farm develops the full cycle of beef cattle production, which is divided into breeding, rearing and finishing. A SWOT analysis (which stands for Strengths, Weaknesses, Opportunities and Threats) was carried out, consisting of an assessment of the property’s internal and external environments. To evaluate the internal environment, an interview was held for data collection by means of questionnaires. The evaluation included: breeding management, sanitary management, nutritional management, infrastructure, workforce, technologies used in pasture formation, conservation and recovery, pasture management and zootechnical indices. To analyze the external environment, a group of people (experts) with deep knowledge of the subject addressed during the study was used as source of information. A matrix was generated with all the information from the SWOT analysis, strengths, weaknesses, opportunities and threats, culminating with the establishment of strategies to increase the productive efficiency of the cattle raising activity.

Effects of carbon‐to‐nitrogen ratio (C:N) on water quality and growth performance of Litopenaeus vannamei (Boone, 1931) in the biofloc system with a salinity of 5‰

This study aimed to investigate the effects of carbon-to-nitrogen ratio (C:N) on water quality and shrimp growth performance during the grow-out culture of Litopenaeus vannamei in a biofloc system under a low salinity condition. Three biofloc treatments with a C:N (contained in feed and exogenous carbon source with the assumption that 75% of the feed nitrogen is excreted) of 8:1 (CN8), 16:1 (CN16) and 24:1 (CN24), respectively, were designed to stocking shrimp juveniles (~0.8 g shrimp−1) at a density of 270 individuals m−3, for a 63-day culture experiment at a salinity of about 5‰. Water parameters were monitored, and zootechnical indices were determined in the three treatments. Results showed that in CN8 treatment, pH, carbonate alkalinity, biofloc volume and TSS were significantly lower (p < 0.05), whereas TAN, nitrite and nitrate were significantly higher, than those in the other two treatments (p < 0.05). The zootechnical parameters of shrimp were not significantly different among the three treatments (p > 0.05), except that the survival rates in CN16 treatment (96.8 ± 2.0%) and CN24 treatment (93.7 ± 4.2%) were significantly higher than that of CN8 treatment (81.5 ± 6.4%, p < 0.05). Regression analysis revealed that the optimal C:N range for pH, SVI (sludge volume index), TAN, nitrate and survival rate was 20.5:1, 18.5:1, 21.0:1, 20.8:1 and 18.6:1. The results suggested that the C:N higher than 16 were suitable for culturing L. vannamei in the biofloc system with a salinity of 5‰, with an optimal range of 18.5–21.0:1.

Morphological characterization of remaining specimens of the Curraleiro horse in Central Brazil

This study aimed to carry out the morphological characterization of the remaining specimens of the Curraleiro horse in municipalities of the state of Goiás, Brazil. Forty male horses were evaluated using the age of five years as a criterion. Sixteen linear measurements and 13 zootechnical indices were obtained. Subsequently, the mean, standard deviation, minimum, maximum, and covariances of these measures and indices were obtained using the software IBM SPSS Statistics for Windows. The measures withers height (WH), croup height (CH), midback height (MH), sternum-to-ground height (SH), chest index (CI), and estimated weight (W) allowed characterizing Curraleiro horses as small-sized, light, and fast, with proportional measures. The dactyl-thoracic index (DTI), body index (BI), conformation index (CFI), load index 1 and 2 (LOI1 and LOI2), and compactness index 1 and 2 (COI1 and COI2) showed that the Curraleiro horse has an intermediate capacity for speed and strength, bearing considerable weight on the back, with saddling aptitude and fast work. These results represent the beginning of the formation of a database that may contribute to future studies and the conservation of the Curraleiro horse in the state of Goiás.

Zootechnical indices and digestibility in juveniles of tambaqui Colossoma macropomum fed a diet containing particulate maize.

Three experiments were done with different particle sizes of corn feed on its zootechnical performance, passing rate and apparent digestibility of juvenile tambaqui (Colossoma macropomum). In the first, 200 juveniles were used and distributed in 20 tanks (220 L), 10 fish per unit (four replicates). The experimental system used to record passage time was composed of five incubators with 200 L. In the second, 75 juveniles were used per 55 days (three replications). In the third, 75 juveniles were used and distributed in five incubators of 200 L. All experiments were performed randomly. Different linear behavior treatments were observed for apparent digestibility of crude protein; and the smaller particle size (150 μm) had better results digestibility. smaller particle size of the corn had better results, affected the growth performance of tambaqui and the apparent digestibility of crude protein and ether extract. Thus, is recommended that a particle size of 150 μm of corn be used for tambaqui.

Calcium carbonate addition reduces nitrite toxic effects in pacu Piaractus mesopotamicus juveniles

This study aimed to assess whether the addition of calcium carbonate (CaCO3) to increase Calcium levels reduces the long-term nitrite (NO2−) toxicity in pacu Piaractus mesopotamicus juveniles. The fish were exposed for 60 days to six treatments comprised by the interaction of three NO2− concentrations (0, 15 and 30 NO2−-N mg L−1) and two Calcium levels (60 and 150 CaCO3 mg L−1), all in triplicate. The zootechnical indices, as well as blood and oxidative stress parameters were evaluated at the end of experimental period. The results showed that at lower hardness, NO2− exposure led to enhanced lipid peroxidation (LPO) levels of muscle and gills and compromised the food conversion rate. Otherwise, the LPO levels were kept at basal condition and no changes were found in zootechnical parameters at higher hardness treatments. Thus, the increase in Calcium levels up to 150 CaCO3 mg L−1 using CaCO3 may reduce the NO2− toxic levels in pacu juveniles, and may be an interesting strategy of water quality management, especially in intensive production systems.

Effect of feed processing during the nursery rearing of the Nile tilapia (Oreochromis niloticus)

This study aimed to compare 5 feed processing for O. niloticus fingerlings: ME1: micro-extruded 1 mm; ED03: extruded and disintegrated 0.3 mm; ED06: extruded and disintegrated 0.6 mm; BF03: bran 0.3 mm and BF06: bran 0.6 mm. Feed conversion was lower in ME1 and ED06. The protein retention coefficient was statistically higher in ME1. The fish proximate composition did not differ among treatments. Although superior in ME1 weight gain did not differ statistically from ED06. ME1 resulted in nitrogen and phosphorus in water statistically lower. ME1, ED06 and BF06 obtained the highest partial net revenues. Thus, ME1 presented the best zootechnical indices, economic performance and reduced impact on water quality.