This study aimed to evaluate barbatimão bark extracts as a feed additive and substitute for lasalocid sodium (LAS) for feedlot lambs. Lambs were distributed into three treatments: LAS (0.018 g of lasalocid sodium), DBB (1.500 g of dried and milled barbatimão bark), and BHE (0.300 g of barbatimão hydroalcoholic extract). There was no effect (p = 0.32) of the inclusion of DBB and BHE extracts on the average daily gain. Inclusion of BHE in lamb diets reduced (p < 0.05) the fatness score compared to LAS, which was similar to DBB. The BHE decreased the yellowness intensity and hue angle (p < 0.05) of meat compared to the LAS. Animals that consumed DBB and BHE had a reduced (p = 0.04) total cholesterol level. Thus, the use of barbatimão bark extracts can replace lasalocid sodium in the diet of feedlot lambs, with no detrimental effects on performance or metabolic parameters.

Anti-nutritional factors are substances that even in vestigial state, reduce or prevent the use of a nutritional element. These anti-nutritional factors, most of which are secondary metabolites, which can be defined as compounds that have no recognized role in the maintenance of vital plant processes that synthesize them, in contrast, play an important role in the interaction of the plant with its environment. Anti-nutritional factors are usually not seen with "good eyes". Although the term anti-nutritional factors refer only to the "bad" characteristics of these substances, it is worth remembering that they are not only responsible for generating adverse effects. On the contrary, virtually all of them, if not all, are capable of conferring, also, possible beneficial effects to the animal organism. Some phenolic compounds of greater representativeness in the animal feed, are: tannins, lignins and gossypol. However, there are also saponins, mimosins, phytate, lectins, protease inhibitors and cyanogenic glycosides. All present in the plants, each with its particularity that will be explained throughout this review.

Tannins have been used to trigger positive effects on ruminal metabolism and increase ruminant production efficiency, since they increase the supply of dietary protein in the small intestine. Increasing levels of tannic acid in a sorghum-based diet on the feeding behavior of five Holstein/Zebu crossbred lactating dairy cows was evaluated. They were subjected to a 5 × 5 Latin square experimental design, with fivelevels of tannin as dry matter (DM) in the diet (0.46, 1.30, 2.60, 3.90, and 5.20%). The levels of the tannic acid added were established based on the quantity of condensed tannin in high-tannin sorghum. Thus, diets 2, 3, 4 and 5 were supplemented with 1.5 g (13% DM), 79.5 g (2.6% DM), 157.5 g (3.9% DM), and 235.5 g (5.2% DM) of tannic acid, totaling 0.078, 0.156, 0.234, and 0.321 kg of tannin/day, respectively. Feeding behavior variables included the following states and events: feeding, drinking, rumination, and inactivity; the frequency of visiting the feed and water troughs; and the occurrence of urination and defecation. Water was provided ad libitum, and its intake was measured during periods of behavioral data collection. The use of two tannin sources (hydrolysable and condensed) corresponding to the total level of 5.20% (on a DM basis) in the diet of lactating dairy cattle does not affect the animals’ health. Tannic acid can be included in the diet of lactating dairy cattle at a level of 3.93% (on a DM basis) without inducing variation in the total time spent daily on feed intake. Dairy cows dilute the effects of dietary tannin (5.20%) through greater fragmentation of food consumption in the hours following its supply (180 min). The astringent effects caused by tannin intake in lactating dairy cows are mitigated by increasing the daily water intake as the amount of tannin in the diet increases, starting at a level of 3.90% tannin (on a DM basis).

The present research objective was to evaluate the performance and blood parameters of lactating cows fed with a diet of two tannin sources, based on sorghum (condensed tannin) with increasing concentrations of tannic acid (hydrolyzable tannin’s). Increasing levels of tannic acid in a sorghum-based diet for five Holstein/Zebu crossbred lactating cows were subject to a 5 × 5 Latin square experimental design. To assess the effect on cow intake, digestibility, milk production, and blood parameters. All cows received 9.87 kg/DM of corn silage as roughage and 6.38 kg of concentrate consisting of 2.58 kg/DM of ground sorghum 0.87 kg/DM of cornmeal 1.32 kg/DM of soybean bran 0.44 kg/DM of wheat bran 0.2 kg/ DM of urea and 0.18 kg/ DM of mineral mixture. Diet 1 (control) contained low-tannin sorghum and the other diets contained high-tannin sorghum. The levels of tannic acid added to the diets were established based on the quantity of condensed tannin in high-tannin sorghum. Thus, diets 2, 3, 4 and 5 were supplemented with 1.5g (13.%DM), 79.5g (2.6%DM), 157.5g (3.9%DM) and 235.5g (5.2%DM) of tannic acid, totalling 0.078, 0.156, 0.234 and 0.321 total tannin kg/day respectively, to assess the effect on microbial protein synthesis. The diets contained 35 kg of corn silage (roughage) and 6.40 kg of concentrate. The natural and dry matter intake did not significantly differ between groups, except for ether extract (EE) intake that significantly differed. The DM apparent digestibility, crude protein, EE, neutral detergent fiber, total carbohydrate, and non-fibrous carbohydrate did not differ (P > 0.05) with the increase in dietary tannin supplementation. The GOT levels increased linearly. The blood glucose, triglyceride, and cholesterol (total, LDL and HDL) levels did not significantly differ. Hemoglobin showed a significant difference. No significant difference in urea, creatinine and uric acid occurred. Diets using two tannins sources supplementation caused no decrease in the dietary intake or digestibility in the animals. The GOT level changed significantly, showing linear behavior, however below the toxicity level, without any change in the other blood parameters. Milk production decreased with the increase in dietary tannin supplementation.