Andrei Lucas Rebelatto Brunetto

Heat stress compromises performance, physiological homeostasis, and welfare in feedlot cattle, stimulating the search for nutritional strategies capable of improving thermal adaptation. This study evaluated the effects of a multi-component phytogenic feed additive, provided alone or in combination with monensin and virginiamycin, on growth performance, hematological and biochemical variables, oxidative status, thermoregulatory responses, and behavior of young Holstein cattle raised during the summer-to-autumn transition in southern Brazil conditions. Thirty-three castrated Holstein steers (10 months of age; 307.1 ± 8.58 kg) were allocated to one of three dietary treatments (n = 11 per treatment): a control diet without additives (GCON), a diet containing the phytogenic additive (GPHY), or a diet containing the phytogenic additive combined with antibiotic growth promoters (GPHY+ANT). The experimental period lasted 80 days, including 15 days of adaptation. The GPHY+ANT group exhibited greater body weight gain than the control during the adaptation period (days 1–15 p = 0.050), whereas cattle receiving the phytogenic additive alone showed greater body weight gain and average daily gain than the control between days 15 and 46 (p = 0.050). Feed intake, feed efficiency, and final body weight were not affected by treatment. Hematological variables remained unchanged, while serum albumin, cholesterol, and triglyceride concentrations were greater in both phytogenic-treated groups than in the control (p ≥ 0.05). Although no overall treatment effect was observed for serum TBARSs or reactive oxygen species (ROS), treatment × day interactions were detected (TBARSs, p = 0.050; ROS, p = 0.010). On day 15, both phytogenic-treated groups exhibited lower TBARS and ROS concentrations than the control group, whereas on day 46, TBARS concentrations were higher in the GPHY+ANT group than in the control group. Cattle receiving the phytogenic additive, either alone or in combination with antibiotic growth promoters, exhibited lower surface temperature, reduced nighttime respiratory rate, and a greater proportion of rumination than control animals (p ≥ 0.05). For standing and lying behaviors, only GPHY+ANT differed from the control, spending less time standing and more time lying (p ≤ 0.05), whereas GPHY showed intermediate values. Additionally, cattle in the GPHY+ANT group spent less time standing and more time lying than control animals (p ≤ 0.05). These findings demonstrate that the phytogenic feed additive improved behavioral and thermoregulatory responses under summer-to-autumn conditions and promoted transient improvements in growth performance during specific stages of the feeding period, without affecting final body weight, overall growth performance, feed intake, or feed efficiency.

This study evaluated the effects of dietary inclusion of free and protected acid protease on productive performance, milk composition, metabolic profile, nutrient digestibility, and ruminal environment in lactating Jersey cows. Fifteen multiparous cows (67 ± 7.5 days in milk; 27.5 ± 3.5 kg/day) were assigned to a 3 × 3 Latin square (5 squares) design with 21-day periods. Treatments consisted of: control (no enzyme), free protease (4.4 g/day), and protected protease (4.4 g/day). The protected form was developed using alginate-based encapsulation to enhance enzyme stability under ruminal conditions. Protease inclusion did not affect dry matter intake, milk yield, or feed efficiency (p > 0.05). However, free protease increased lactation persistency (p = 0.05) and improved fat-corrected and energy-corrected milk yields (p ≤ 0.02), with intermediate responses observed for protected protease. Milk fat and protein contents were higher in enzyme-fed cows (p ≤ 0.05), while other compositional parameters remained unchanged. Apparent crude protein digestibility was greater in cows receiving free protease (p = 0.037), with no effects on dry matter or fiber digestibility. Protease intake increased total volatile fatty acid concentrations and major fermentation products (acetate, propionate, and butyrate; p ≤ 0.01), indicating enhanced ruminal fermentation. Blood metabolites showed increased total protein and globulin levels in cows fed free protease (p ≤ 0.05), suggesting improved protein metabolism. Microbiota analysis revealed no differences in alpha or beta diversity; however, specific microbial taxa and predicted metabolic pathways were modulated by treatments, particularly in post-ruminal compartments. In conclusion, exogenous protease, especially in free form, improved protein utilization and corrected milk production without disrupting microbial stability. These findings highlight the potential of protease as a nutritional strategy to enhance efficiency in dairy systems through targeted modulation of ruminal function and nutrient metabolism.

The use of exogenous enzymes in feedlot cattle nutrition has been investigated as a strategy to increase nutrient utilization efficiency and productive performance. The objective of this study was to evaluate the effects of including arazyme, an exogenous metalloprotease, in the diet of feedlot beef cattle on zootechnical performance, hematological parameters, serum biochemical biomarkers, ruminal fermentation, and apparent nutrient digestibility. Twelve male Holstein cattle, with an average initial body weight of 352.5 ± 20.6 kg, were distributed in a completely randomized design with two treatments: control (no additive) and basal diet with arazyme (0.67 g/kg of dry matter consumed) for 63 days. The diet was formulated with a forage/concentrate ratio of 40:60. Although the sample size was small, the inclusion of arazyme proved effective under these conditions, with animals receiving the enzyme showing greater total weight gain, higher average daily gain, and better feed conversion, without affecting dry matter intake. No significant changes were observed in hematological parameters or in most serum biochemical biomarkers, indicating an absence of adverse effects on the metabolic or hepatic health of the animals. Higher total concentrations of volatile fatty acids in the rumen, particularly acetic, propionic, and butyric acids, as well as a higher ruminal pH on day 63, may be related to the enzyme’s action. Additionally, the apparent digestibility of crude protein and neutral detergent fiber was higher. Therefore, the inclusion of arazyme in the diet of feedlot cattle may be a promising alternative for improving digestive efficiency and intensifying ruminal fermentation, potentially resulting in improved productive performance. Future research with a larger number of replicates and different doses of the additive is necessary to understand its action.

Although a yeast-based additive was initially employed as a performance enhancer, subsequent analysis revealed high aflatoxin B1 levels in the corn silage. Therefore, the objective of this study is to determine if the use of a yeast blend in the diet of Holstein calves that consumed feed naturally contaminated with high levels of aflatoxin can minimize the negative impacts of mycotoxins on animal health, contributing to improved performance. For this, we used 24 Holstein calves (6 months old) divided into two groups: Control (n = 12; no additive) and Treatment (n = 12; 5 g additive/animal/day). During the 100-day experiment, animals were weighed, feed intake was measured, blood samples were collected to assess health, and ruminal fluid was analyzed for ruminal fermentation. We observed greater weight gain and better feed efficiency in cattle that consumed the yeast-based additive compared to the control group. Yeast ingestion increased the concentration of propionic acid in the experimental environment, as well as increasing the protozoan count. Higher lymphocyte counts combined with higher levels of immunoglobulin G in the blood of females that consumed the additive were observed. Lower activity of enzymes that are biomarkers of liver damage, as well as markers of oxidative stress, was observed when animals consumed the yeast blend compared to the control group. Lower levels of ceruloplasmin (positive acute phase protein) and higher levels of transferrin (negative acute phase protein) are indicative of an anti-inflammatory response to the additive. The results preliminarily suggest that the consumption of the yeast blend is a nutritional tool capable of acting as a performance enhancer, even under challenging conditions, such as diets contaminated with aflatoxin at levels exceeding international limits.

During the grain and cereal production process, whether during harvesting, processing, or storage, errors can occur, compromising product quality and potentially leading to contamination by fungi, which produce toxic substances known as mycotoxins. When fed to animals, these contaminated grains and cereals can cause several negative effects on animal health, impacting their production performance, including immunosuppression, hepatotoxicity, nephrotoxicity, and reproductive problems. To minimize the problems caused by mycotoxins, anti-mycotoxin additives, also known as adsorbents, are used. These are inert materials that bind to mycotoxins and are excreted in feces, preventing their action within the animal’s body. Therefore, the objective of this study was to evaluate the effectiveness of an anti-mycotoxin product based on bentonite, activated charcoal, milk thistle extract, and yeast cell wall in the diet of mycotoxin-contaminated lambs on animal health and performance. Thirty lambs were divided into three homogeneous groups: control (without mycotoxins or additives), mycotoxin (with mycotoxins), and anti-mycotoxin (mycotoxins and additive). The mycotoxins used for feed contamination were aflatoxin (AFLA) (200 ppb), fumonisin (FUMO) (15 ppm), zearalenone (ZEA) (500 ppb), and deoxynivalenol (DON) (1.5 ppm). The anti-mycotoxin additive was used at a dose of 1 kg/ton of concentrate. Parameters of zootechnical performance, hematological profile, serum biochemistry, and oxidative status were evaluated. The group that ingested the contaminated concentrate with mycotoxin had a lower average daily weight gain (ADG) when compared to the control and anti-mycotoxin groups. Ingestion of a mycotoxin-contaminated diet increased the activity of aspartate aminotransferase and gamma-glutamyltransferase, which are indicators of liver damage. However, when the anti-mycotoxin additive was used, the increase in these enzymes was modest and lower than in the mycotoxin group. Ingestion of a mycotoxin-containing concentrate increased levels of oxidative stress biomarkers such as reactive oxygen species (ROS), thiobarbituric acid reactive substances (TBARS), myeloperoxidase (MPO), and reduced glutathione (GST), demonstrating that the mycotoxin challenge was effective in causing oxidative stress. However, when the diet was contaminated with mycotoxins and supplemented with the anti-mycotoxin additive, the levels of ROS and TBARS were similar to those of the negative control group. We concluded that adding the anti-mycotoxin product to the lambs’ diets prevented or minimized the problems caused by mycotoxin consumption, allowing these lambs to have ADG, and feed efficiency similar to the control group.

The use of exogenous enzymes in the nutrition of dairy cows is an innovative and efficient strategy to maximize productivity and milk quality, with positive applications in the economic and environmental aspects of dairy farming. Therefore, the objective of this study was to evaluate whether the addition of a blend of exogenous enzymes to the diet of lactating Jersey cows has a positive effect on productive performance, milk quality, animal health, ruminal environment, and digestibility. Twenty-one primiparous Jersey cows, with 210 days in lactation (DL), were used. The exogenous enzymes used were blends containing mainly protease, in addition to cellulase, xylanase, and beta-glucanase. The animals were divided into three groups with seven replicates per group (each animal being the experimental unit), as follows: Control (T-0), basal diet without enzyme addition; Treatment (T-80), animals fed enzymes in the diet at a daily dose of 80 mg per kg of dry matter (DM); Treatment (T-160), animals fed enzymes in the diet at a daily dose of 160 mg per kg of DM. The study lasted 84 days, during which higher milk production was observed in the treated groups (T-80 and T-160) compared to the control group (p = 0.04). When calculating feed efficiency from days 1 to 84, greater efficiency was observed in both groups that received the blend compared to the control (p = 0.05). In the centesimal composition of the milk, it was observed that the percentage of protein in the milk of the T-160 group was higher compared to the control group (p = 0.03). The effect of the enzymes was verified for butyric (p = 0.05) and palmitic (p = 0.05) fatty acids. We also observed the effect of the enzyme blend on the amount of volatile fatty acids (VFAs), which were higher in the ruminal fluid of cows that received the enzymes (p = 0.01). Cows that consumed enzymes showed a higher apparent digestibility coefficient of crude protein (p = 0.01). In vitro, the main result is related to lower gas production in 24 and 48 h at T-160. We concluded that the use of a blend of exogenous enzymes in the diet of lactating Jersey cows was able to increase milk production in these animals, resulting in greater feed efficiency and also an increase in milk protein content, positively modulating the fatty acid profile in the rumen and improving the apparent digestibility of nutrients.

The growing demand for biofuels, especially ethanol produced from corn, has driven the production of co-products such as dried distillers grains with solubles (DDGS). With a high protein content (around 30%), fiber, and minerals, DDGS presents an economical alternative for animal nutrition, replacing traditional sources like soybean meal while maintaining productive performance and reducing costs. This study evaluated the total replacement of soybean meal with DDGS in the diet of confined Holstein cattle, focusing on weight gain, feed intake, digestibility, feed efficiency, animal health, meat quality, and economic viability. The 24 animals received diets with 80% concentrate, containing either DDGS or soybean meal, and no significant differences were observed in terms of body weight (p = 0.92), feed intake (p = 0.98), or feed efficiency (p = 0.97) between the two treatments. The average daily gain was 1.25 and 1.28 kg for cattle in the DDGS and soybean meal groups, respectively (p = 0.92). Regarding metabolic and digestive parameters, no relevant changes were found in blood levels, except for higher serum cholesterol (p = 0.03) levels in animals fed DDGS. The digestibility of neutral detergent fiber (NDF) (p = 0.03) and acid detergent fiber (ADF) (p = 0.05) was lower in the DDGS group, while the digestibility of ether extract was higher (p = 0.02). Rumen fluid analysis revealed an increase in the production of short-chain fatty acids (p = 0.01), such as acetic and butyric acids (p = 0.01), in the DDG-fed animals. In terms of meat quality, animals fed DDGS produced meat with lower levels of saturated fatty acids (SFA) (p = 0.05) and higher levels of unsaturated fatty acids (UFA) (p = 0.02), especially oleic acid (p = 0.05). This resulted in a healthier lipid profile, with a higher UFA/SFA ratio (p = 0.01). In terms of economic viability, DDGS-based diets were 10.5% cheaper, reducing the cost of production per animal by 7.67%. Profitability increased by 110% with DDGS compared to soybean meal, despite the high transportation costs. Therefore, replacing soybean meal with DDGS is an efficient and economical alternative for feeding confined cattle, maintaining zootechnical performance, increasing meat lipid content and improving fatty acid profile, and promoting higher profitability. This alternative is particularly advantageous in regions with easy access to the product.

This study determined whether organic zinc and selenium supplementation of late lactation dairy cows positively affects immunity, oxidative status, milk quality (especially mineral levels), biochemical and hematologic parameters, and production efficiency. Twenty Jersey cows were divided into three groups: Control (n = 6)—without organic supplementation; Zinc (n = 7)—zinc supplementation (zinc amino acid chelate) and Selenium (n = 7)—selenium supplementation (selenium amino acid complex). The basal diet contained inorganic minerals. Blood and milk samples were collected on days 1, 14 and 28. Serum selenium concentration was higher in the Selenium group, and zinc level in milk was higher in the Zinc group. On day 28, supplementations resulted in higher lymphocyte counts, and lower serum creatine kinase, myeloperoxidase activity, levels of reactive oxygen species, thiobarbituric acid-reactive substances, and iron. In milk, lower somatic cell count was also observed when cows were zinc or selenium supplemented compared to the control. Lower serum cholinesterase activity and higher heavy chain immunoglobulin concentration were observed on days 14 and 28. Selenium supplementation resulted in a higher immunoglobulin A concentration on days 14 and 28, and lower ceruloplasmin concentration on day 28 compared to Control, as well as a lower haptoglobin concentration on day 28. The Selenium group also had lower milk fat content compared to the Control. Supplementations changed the milk fatty acid profile, producing a higher unsaturated fatty acid/saturated fatty acid ratio. There was no effect on lactation persistence. It is concluded that mineral supplementation with selenium and zinc benefits immune, antioxidant, and anti-inflammatory responses. Conversely, milk quality was affected both positively and negatively.

This study determined whether adding condensed tannins to the diet of confined lamb improves performance, metabolism, health, and meat composition and quality. We used 24 Lacaune lambs with an average initial weight of 24.5 ± 0.24 kg. The animals were divided into 12 pens with two animals each. In the treatment group, a black wattle extract was added to the lamb concentrate (2.5 g/kg dry matter), while the control group received only the basal diet (without extract). Black wattle contained 98.6 g/kg of condensed tannin. There was no difference between the performance variables, which included weight gain, feed intake, and feed efficiency. However, the group fed on condensed tannins showed higher carcass yield and a higher percentage of linked intramuscular fat. In meat, a lower proportion of saturated fatty acids combined with higher concentrations of unsaturated fatty acids was observed in lambs of the condensed tannin group. The polyunsaturated fatty acids (PUFA) were no different; however, a higher PUFA/SFA ratio was observed in animals with condensed tannin intake, and a higher proportion of ω6 and ω3 was observed in the meat of these animals. The meat’s protein and ash content did not differ between treatments, as did the meat’s water retention capacity, color, and luminosity. Furthermore, animals that fed on condensed tannins had lower cholesterol levels and higher globulin content. The values of erythrogram variables were lower in lambs that consumed condensed tannins. More significant ruminal bacterial activity was also observed in the group receiving condensed tannins. The antioxidant effect was verified with lower thiobarbituric acid reactive species (TBARS) levels and more significant antioxidant enzyme activity. We conclude that adding condensed tannins improves carcass yield and increases the percentage of fat in the carcass, improving the fatty acid profile, which may be linked to the antioxidant effect, in addition to the health benefits of the consumer of this product.

Background: This study aimed to verify whether adding a combination of additives (blend) to the diet of dairy calves after weaning can improve animal performance and health and influence the profile of ruminal short-chain fatty acids and intestinal microbiota. Methods: We used 35 Holstein calves, males, with an average age of 70 days and an average body weight of 68 kg. The treatments used were negative control (T-0: without additive), positive control (T-Control: flavomycin + monensin), T-500 (500 g blend/ton), T-1000 (1000 g blend/ton), and T-1500 (1500 g blend/ton). The additives were classified as zootechnical (probiotics, prebiotics, and essential oils of cinnamon and oregano) and nutritional additive (minerals). Results: Weight gain and daily weight gain were higher for calves in the T-Control, T-500, and T-1000 groups. The concentration of heavy-chain immunoglobulins was higher in the blood of calves in the T-Control and T-500 groups when compared to the other groups. In the T-1500 groups, higher levels of reactive oxygen species were observed, while, in the T-0 and T-1500 groups, higher levels of TBARS and glutathione S-transferase activity were detected. The 15 abundant microorganisms in the calves’ feces, regardless of treatment, were Treponema suis, Treponema saccharophilum, Faecalibacterium prausnitzii, Pseudoflavonifractor sp., Roseburia faecis, Rikenellaceae, Enterobacteriaceae_f, Clostridium sp., Roseburia intestinalis, Aeromonadales_o, Prevotella copri, Treponema succinifaciens, Eubacterium sp., Treponema porcium, and Succinivibrio sp. The T-1000 group showed greater alpha diversity for the intestinal microbiota than T-Control, T-0, and T-500. The additive combination (T-1000) increased the bacterial activity in the ruminal fluid, and the animals of T-1000 had a higher concentration of short-chain fatty acids compared to T-0 and T-1500; this difference is because, in these calves, the production of acetic, butyric, and propionic acid increased. Conclusions: The combination of additives had positive effects on animal health, ruminal volatile fatty acid production, and intestinal microbiota, resulting in animals with more significant weight gain and feed efficiency.