Ronaldo Lopes Oliveira

This study evaluated the effects of tamarind (Tamarindus indica L.) pulp as a marinade on the physicochemical quality (marinade liquid uptake, water-holding capacity, cooking loss, proximate composition, water activity, pH, color, and texture), oxidative stability (lipid oxidation), microbiological characteristics (mesophilic aerobic counts, Enterobacteriaceae, Gram-positive cocci, and molds and yeasts), and sensory attributes of eye of round beef (M. semitendinosus). Three treatments were compared: non-marinated control (C), brine (B; 2.5% NaCl), and NaCl with tamarind pulp (BPT; 2.5% NaCl + tamarind pulp). Tamarind incorporation significantly reduced pH and water-holding capacity, resulting in lower moisture content and higher ash and carbohydrate levels. BPT samples exhibited increased lightness (L*) and yellowness (b*) and reduced redness (a*), reflecting pigment contribution and acid-induced structural modifications. Texture profile analysis showed lower hardness and chewiness in BPT throughout storage, demonstrating improved tenderness. Lipid oxidation increased in B but remained controlled in BPT, highlighting the antioxidant potential of tamarind pulp. Tamarind selectively improved the microbiological profile by inhibiting Enterobacteriaceae and reducing mesophilic aerobic bacteria, although it was less effective in controlling molds and yeasts. Sensory evaluation showed that B treatment received the highest scores for flavor and overall acceptability, while BPT was characterized by fruity, acidic, and sweet notes, resulting in a distinctive sensory profile without reducing acceptability relative to the control. Overall, tamarind pulp substantially modulated the quality characteristics of marinated eye of round beef, providing advantages in oxidative stability, microbial control, and texture while also reducing water-holding capacity, altering color, increasing mold and yeast growth, and producing a distinctive sensory profile. These findings highlight both the potential and the limitations of tamarind pulp as a natural ingredient for clean-label meat products.

The synchronization between nitrogen sources and carbohydrate fractions represents a critical factor for optimizing microbial protein synthesis and overall ruminant performance. This systematic review, conducted according to PRISMA 2020 guidelines, comprehensively evaluated the interactions between different nitrogen sources (true protein, urea, controlled-release urea, and bypass amino acids) and carbohydrate fractions (rapidly degrading soluble, slowly degrading soluble, fibrous, non-fibrous, and Van Soest fractions) in ruminant nutrition. A comprehensive search across PubMed, ScienceDirect, Web of Science, and Scopus databases identified 1855 records, of which 164 studies met the eligibility criteria for qualitative synthesis and 89 for quantitative meta-analysis. The review reveals that synchronization effectiveness varies significantly depending on the nitrogen source–carbohydrate combination, with controlled-release urea showing superior synchrony with slowly degrading carbohydrates, while conventional urea performs better with rapidly degrading sources. Meta-analytical results indicate that optimal nitrogen–carbohydrate synchronization can improve microbial protein synthesis by 18–34%, reduce urinary nitrogen excretion by 12–28%, and enhance feed efficiency by 8–15%. These findings provide evidence-based recommendations for precision nutrition strategies in ruminant production systems.

This study aimed to evaluate the effect of increasing levels of Acacia mearnsii extract as a source of condensed tannins on feed intake, nutrient digestibility, nitrogen (N) balance, rumen fermentation, and blood parameters of feedlot‐finished cattle. Eight rumen‐cannulated bulls were distributed in a replicated 4 × 4 square Latin design. The treatments consisted of a control diet with no extract inclusion (0 g/kg) and three diets with 10, 30, and 50 g/kg on a dry matter (DM) basis of A. mearnsii extract. Adding A. mearnsii extract to the diet linearly reduced ( p < 0.05) the intake of DM, crude protein (CP), extract ether (EE), neutral detergent fiber (NDF), non‐fiber carbohydrate (NFC), and total digestible nutrient (TDN); however, it linearly increased ( p < 0.05) the digestibility of DM, NDF, and NFC. Including extract in the diet linearly reduced N‐intake and N‐urinary excretion and increased quadratically fecal N excretion ( p < 0.05). Ruminal ammonia nitrogen (RAN) concentration and short‐chain fatty acids were not affected ( p > 0.05), but ruminal pH and serum proteins linearly decreased ( p < 0.05) with the inclusion of extract. Including A. mearnsii extract in the diet of cattle at levels up to 50‐g/kg DM reduces intake and increases the utilization of the feed and its nutrients.

This study investigated whether supplying rumen-protected lysine (RPL), alone or in combination with tannins, could modify the fatty acid (FA) profile, physicochemical characteristics, carcass traits, and sensory attributes of lamb meat. Forty Santa Inês × Dorper lambs (≈23 kg, 4 months old) were assigned to four dietary treatments for 55 days: a control diet, free lysine (0.44%), RPL microencapsulated in a carnauba-wax matrix, and RPL + tannins blend (1.34%). Feed intake, carcass weight, and quantitative carcass measurements did not differ among treatments (p > 0.05). Likewise, pH, color, proximate composition, water-holding capacity, cooking losses, and shear force remained unchanged. Dietary supplementation influenced the FA composition of the meat. RPL, especially when added with tannins, increased concentrations of conjugated linoleic acid (C18:2 cis–9, trans–11), eicosapentaenoic (C20:5 n–3), and docosahexaenoic acids (C22:6 n–3), improving the n–6:n–3 ratio (p < 0.05). The sum and ratio of other FA and cardiometabolic indices were not altered. Lipid oxidation was reduced in RPL treatments, indicating enhanced oxidative stability. Sensory attributes scores were not affected (p > 0.05), ranging from “liked slightly” to “liked very much”. RPL, particularly when combined with tannins, improved specific health-related FA without adversely affecting carcass characteristics or consumer acceptance.

Urea is one of the most widely used sources of non-protein nitrogen (NPN) in ruminant diets due to its low cost and high availability. However, its rapid solubilization in the rumen can result in abrupt ammonia release, leading to toxicity risks and low nitrogen utilization efficiency. In this context, slow-release technologies, particularly microencapsulation, have been developed to synchronize NPN release with fermentable carbohydrate availability, thereby enhancing microbial protein synthesis, improving animal performance, and reducing environmental impacts. This review compiles recent advances in urea microencapsulation, emphasizing different wall materials such as waxes, lipids, polysaccharides, and fatty acids, as well as drying techniques and formulation strategies. Slow-release urea (SRU) addition in small ruminants’ diet may increase nutrient intake and digestibility, improve N balance, and reduce urinary excretion losses. Regarding performance, positive responses are observed when nitrogen release is properly synchronized with energy availability, although the results may vary depending on the encapsulant type, forage-to-concentrate ratio, and ruminal passage rate. Additionally, effects on meat quality and environmental parameters indicate that this technology holds not only zootechnical but also socio-environmental potential. It is concluded that urea microencapsulation can represent a promising alternative to optimize NPN use efficiency in ruminant production systems, though greater methodological standardization, long-term evaluations, and comparative economic analyses are required to encourage its broader adoption.

Antioxidant feed additives, such as cashew nutshell liquid (CNSL), rich in phenolic compounds, have gained attention for improving animal production and meat quality. The study evaluated the dietary effects of blending CNSL (0.5%) with different vegetable oils (1.5%) varying in unsaturated fatty acid (UFA) profiles on the meat quality and fatty acid composition of muttons. Forty Santa Inês × Dorper crossbred rams (24.44 ± 1.5 kg) were allocated to five treatments for 70 days: CNSL combined with canola (MUFA-rich) compared to corn, soybean, sunflower, or cottonseed oils (PUFA-rich). The CNSL + canola blend improved meat quality, showing higher water-holding capacity and tenderness and lower cooking loss than CNSL + PUFA-rich oils (p < 0.05). Meat yellowness (b*) increased with CNSL + soybean or cottonseed blend. Meat proximate composition was unaffected (p > 0.05). Minor variations in specific fatty acids were observed, including higher C14:0 and C16:1 in canola and cottonseed + CNSL blend groups and greater EPA (C20:5 n–3) with soybean oil + CNSL blend (p < 0.05). The ∑n–6:∑n–3 ratio was highest with cottonseed and lowest with soybean oil (p < 0.05). Overall, combining CNSL with MUFA-rich oils, particularly canola, compared to PUFA oils, enhances meat quality while supporting the sustainable use of CNSL in ram diets.

The use of escape protein, which is absorbed in the small intestine, can improve the production of ruminant animals because it meets their protein requirements better. This study hypothesized that wax lipid matrices are effective encapsulants for escape lysine in ruminants and tested tannin extract as an adjuvant. Forty intact male Santa Ines × Dorper sheep (~4 months old, BW 23 ± 1.2 kg) were allocated, in a randomized block design, to four treatments: control group (no lysine addition), supplementation with free lysine, escape lysine, and escape lysine + tannin extract. The ether extract intake was higher in the sheep fed escape lysine + tannin compared to the control and free lysine group. The sheep fed escape lysine presented higher DM and aNDF eating efficiency (p ≤ 0.05) compared to the free lysine and control groups. Escape lysine with and without tannin presented greater TDN compared to free lysine and control. The NFCs were lower in the free lysine diet, and the crude protein digestibility was higher in the sheep fed lysine + tannin and the control group compared to the escape and free lysine groups. The lysine treatments did not affect (p > 0.05) the performance, ingestive behavior, and blood parameters. The rectal temperature was higher in the sheep fed lysine escape compared to those fed free lysine. The sheep fed escape lysine + tannin exhibited reduced (p ≤ 0.05) large particles and improved peNDF 12 h after feeding. The escape lysine diet, regardless of the addition of tannin, improved the total digestible nutrients and eating efficiency, without affecting the performance, feed conversion, and blood variables of the sheep.

Substituting soybean meal (SM) with other protein sources can be advantageous in reducing production costs without increasing nitrogen losses in the environment. Peanut cake (PC) might be a strategy in ruminant herds to result in a performance similar to that observed in animals fed SM. This study assessed the PC inclusion at rates of 0, 250, 500, 750, and 1000 g/kg on intake and digestibility, performance, nitrogen balance, microbial protein synthesis, and carcass traits of lambs. Forty-five entire, crossbreed Dorper × Santa Inês lambs (average age = five months and 24.49 ± 5.27 kg of BW) were distributed in a completely randomized design. Only the ether extract intake was not affected by the PC inclusion, and only the crude protein digestibility was affected by the diets. The total weight and average daily gains decreased, and the feed conversion increased. Hot carcass yield was influenced quadratically, the leg depth increased and the loin-eye area decreased. The total replacement of soybean meal with peanut cake in diets for lambs did not compromise nutrient digestibility, microbial protein synthesis, and carcass characteristics. Nevertheless, peanut cake as a protein source in the diet had adverse effects on nutrient intake and growth performance of feedlot lambs.

Tannins are compounds present in forage plants that, in small quantities in the diet of ruminants, produce protein complexes that promote passage through the rumen and use in the intestine. This study tested the hypothesis that beeswax (BW) and carnauba wax (CW) lipid matrices are effective encapsulants for creating bypass lysine (Lys) for ruminants, with tannin extracted from the Mimosa tenuiflora hay source enhancing material protection. Microencapsulated systems were made using the fusion–emulsification technique with a 2:1 shell-to-core ratio and four tannin levels (0%, 1%, 2%; 3%). The following eight treatments were tested: BWLys_0%, BWLys_1%, BWLys_2%, BWLys_3%, CWLys_0%, CWLys_1%, CWLys_2%, and CWLys_3%. Tannin inclusion improved microencapsulation yield and efficiency. CWLys_3% had the highest microencapsulation efficiency and retained Lys. Lysine in BW and CW matrices showed higher thermal stability than in its free form. Material retention was greater in BW than CW. Rumen pH and temperature remained unaffected, indicating that BW and CW as the shell and tannin as the adjuvant are efficient encapsulants for Lys bypass production. The formulation CWLys_3% is recommended as it is more efficient in protecting the lysin amino acid from rumen degradation.