ABSTRACT

The objective of this study was to evaluate the performance of Nellore bulls finished in the feedlot and fed high-energy diets containing sodium monensin associated or not with tannins and saponins. Ninety-six Nellore bulls were used with an average initial body weight of 350.6±17.9 kg. The bulls were weight-blocked and randomly allocated to 12 pens, which were considered the experimental units. The treatments were assigned to the pens according to the blocks, as follows: sodium monensin (25 ppm; SM) and sodium monensin (25 ppm) plus tannins (350 ppm) and saponins (3.92 ppm, SM+TS). The bulls received an adaptation diet for the first 19 days, a growing diet from day 20 to day 59, and a finishing diet from day 60 to 98 of the experimental period. The animals were slaughtered after 98 days of study. The addition of tannins and saponins to the diets of feedlot Nellore cattle did not change the dry matter intake, hot carcass weight, and dressing percentage; however, it increased body weight by 2.0% and average daily gain by 5.4% and improved feed conversion by 4.3%. The addition of tannins and saponins to high-concentrate diets containing sodium monensin improves the productive performance of Nellore cattle finished in a feedlot for 98 days.

additives; cattle; efficiency; intake

1. Introduction

In general, the feed additives often used in ruminant nutrition aims at modifying ruminal microbiota composition to optimize dietary digestion and synthesis of ruminal end products, such as short-chain fatty acids, and reducing energy losses, resulting in improved feed efficiency, growth rate, and animal performance (Min et al., 2020Min, B. R.; Solaiman, S.; Waldrip, H. M.; Parker, D.; Todd, R. W. and Brauer, D. 2020. Dietary mitigation of enteric methane emissions from ruminants: A review of plant tannin mitigation options. Animal Nutrition 6:231-246. https://doi.org/10.1016/j.aninu.2020.05.002
https://doi.org/10.1016/j.aninu.2020.05.... ).

Sodium monensin is by far the most used feed additive in feedlot diets in Brazil (Silvestre and Millen, 2021Silvestre, A. M. and Millen, D. D. 2021. The 2019 Brazilian survey on nutritional practices provided by feedlot cattle consulting nutritionists. Revista Brasileira de Zootecnia 50:e20200189. https://doi.org/10.37496/rbz5020200189
https://doi.org/10.37496/rbz5020200189... ). Duffield et al. (2012)Duffield, T. F.; Merrill, J. K. and Bagg, R. N. 2012. Meta-analysis of the effects of monensin in beef cattle on feed efficiency, body weight gain, and dry matter intake. Journal of Animal Science 90:4583-4592. https://doi.org/10.2527/jas.2011-5018
https://doi.org/10.2527/jas.2011-5018... reported that the major effects of sodium monensin on beef cattle metabolism include a reduction in dry matter intake (DMI), a decrease in ruminal deamination, and improvements in feed efficiency. Other feed additives that have received attention of the scientists recently are tannins and saponins (Bele et al., 2010Bele, A. A.; Jadhav, V. M. and Kadam, V. J. 2010. Potential of tannins: A review. Asian Journal of Plant Sciences 9:209-214. https://doi.org/10.3923/ajps.2010.209.214
https://doi.org/10.3923/ajps.2010.209.21... ; Cieslak et al., 2014Cieslak, A.; Zmora, P.; Stochmal, A.; Pecio, L.; Oleszek, W.; Pers-Kamczyc, E.; Szczechowiak, J.; Nowak, A. and Szumacher-Strabel, M. 2014. Rumen antimethanogenic effect of Saponaria officinalis L. phytochemicals in vitro. The Journal of Agricultural Science 152:981-993. https://doi.org/10.1017/S0021859614000239
https://doi.org/10.1017/S002185961400023... ), which are secondary plant compounds that do not interfere with the vital metabolism of plants and are present in leaves, bark, fruit, seeds, and sap, but mainly in cell vacuoles. When used in animal feeding, tannins and saponins can reversibly bind to proteins and other larger molecules that break down depending on the pH where these complexes are formed (Min et al., 2020Min, B. R.; Solaiman, S.; Waldrip, H. M.; Parker, D.; Todd, R. W. and Brauer, D. 2020. Dietary mitigation of enteric methane emissions from ruminants: A review of plant tannin mitigation options. Animal Nutrition 6:231-246. https://doi.org/10.1016/j.aninu.2020.05.002
https://doi.org/10.1016/j.aninu.2020.05.... ).

Therefore, plant extracts have the potential to be used in ruminant feeding as feed additives; however, since they are dose-dependent, the correct amount may prevent metabolic disorders without interfering with ingestion, reducing the production of ruminal ammonia and methane, and resulting in an increased flow of aminoacids into the duodenum and improved animal performance (Bele et al., 2010Bele, A. A.; Jadhav, V. M. and Kadam, V. J. 2010. Potential of tannins: A review. Asian Journal of Plant Sciences 9:209-214. https://doi.org/10.3923/ajps.2010.209.214
https://doi.org/10.3923/ajps.2010.209.21... ; Halvorson et al., 2017Halvorson, J. J.; Kronberg, S. L. and Hagerman, A. E. 2017. Effects of dietary tannins on total and extractable nutrients from manure. Journal of Animal Science 95:3654-3665. https://doi.org/10.2527/jas.2016.1129
https://doi.org/10.2527/jas.2016.1129... ; Orzuna-Orzuna et al., 2021b). In addition, saponins may decrease the population of protozoa and methanogens, enhancing the production of volatile fatty acids, especially propionate (Darabighane et al., 2021Darabighane, B.; Mahdavi, A.; Aghjehgheshlagh, F. M.; Navidshad, B.; Yousefi, M. H. and Lee, M. R. F. 2021. The effects of dietary saponins on ruminal methane production and fermentation parameters in sheep: a meta analysis. Iranian Journal of Applied Animal Science 11:15-21.). Furthermore, the concentration of condensed tannins and saponins in the diets of feedlot cattle may result in beneficial or adverse nutritional and physiological effects (Tedeschi et al., 2014Tedeschi, L. O.; Ramírez-Restrepo, C. A. and Muir, J. P. 2014. Developing a conceptual model of possible benefits of condensed tannins for ruminant production. Animal 8:1095-1105. https://doi.org/10.1017/S1751731114000974
https://doi.org/10.1017/S175173111400097... ; Lotfi, 2020Lotfi, R. 2020. A commentary on methodological aspects of hydrolysable tannins metabolism in ruminant: a perspective view. Letters in Applied Microbiology 71:466-478. https://doi.org/10.1111/lam.13346
https://doi.org/10.1111/lam.13346... ). Another factor that may interact with the presence of tannins and saponins in feedlot cattle diets is the presence of sodium monensin, which can decrease ruminal deamination, DMI, and production of ruminal ammonia and methane, resulting in an increased flow of aminoacids into the duodenum and improved animal performance (Tseu et al., 2021Tseu, R. J.; Perna Junior, F.; Carvalho, R. F.; Sene, G. A.; Tropaldi, C. B.; Peres, A. H.; Dos Anjos, F. and Rodrigues, P. H. M. 2021. Effect of tannins and monensin on rumen fermentation and feed energy partitioning of Nellore cows. Iranian Journal of Applied Animal Science 11:669-685.; Yanza et al., 2021 Yanza, Y. R. ; Fitri, A. ; Suwignyo, B. ; Elfahmi ; Hidayatik, N. ; Kumalasari, N. R. ; Irawan, A. and Jayanegara, A. 2021. The utilisation of tannin extract as a dietary additive in ruminant nutrition: A meta-analysis. Animals 11:3317. https://doi.org/10.3390/ani11113317
https://doi.org/10.3390/ani11113317... ).

In Brazil, Nellore bulls are the most used animal type in feedlot operations for finishing purposes (Silvestre and Millen, 2021Silvestre, A. M. and Millen, D. D. 2021. The 2019 Brazilian survey on nutritional practices provided by feedlot cattle consulting nutritionists. Revista Brasileira de Zootecnia 50:e20200189. https://doi.org/10.37496/rbz5020200189
https://doi.org/10.37496/rbz5020200189... ), and just recently they started to be slaughtered close to the mature weight (NASEM, 2016NASEM - National Academies of Science, Engineering and Medicine. 2016. Triennial review of the national nanotechnology initiative. National Academies Press, Washington, DC.). Thus, the association of tannins and saponins with sodium monensin in feedlot diets may promote positive effects on the performance of feedlot cattle in Brazil, since Nellore bulls, even in the finishing period, may still benefit from the increased flux of dietary aminoacids into the small intestine. Very few studies that evaluated the effects of the association of tannins and saponins with sodium monensin in the diets of feedlot cattle have been carried out (Rivera-Méndez et al., 2017Rivera-Méndez, C.; Plascencia, A.; Torrentera, N. and Zinn, R. A. 2017. Effect of level and source of supplemental tannin on growth performance of steers during the late finishing phase. Journal of Applied Animal Research 45:199-203. https://doi.org/10.1080/09712119.2016.1141776
https://doi.org/10.1080/09712119.2016.11... ; Koenig et al., 2018Koenig, K. M.; Beauchemin, K. A. and McGinn, S. M. 2018. Feeding condensed tannins to mitigate ammonia emissions from beef feedlot cattle fed high-protein finishing diets containing distillers grains. Journal of Animal Science 96:4414-4430. https://doi.org/10.1093/jas/sky274
https://doi.org/10.1093/jas/sky274... ).

We hypothesize that the combination of condensed tannins (in a lower dose) and saponins with sodium monensin may reveal a synergistic effect and then maximize the feedlot performance of Nellore cattle. In this context, the objective of this study was to evaluate the effects of the addition of condensed tannins and saponins associated with sodium monensin on animal performance and carcass characteristics of Nellore cattle finished in a feedlot.

2. Material and Methods

Research on animals was conducted according to the Institutional Ethics Committee on the Use of Experimental Animals (CEUA Protocol 21/2022). The experiment was carried out in Presidente Bernardes, SP, Brazil, in a circumscribed area defined by the coordinates 22°00'22" S latitude, 51°33'11" W longitude, and 429 m elevation.

Ninety-six Nellore bulls, with an initial body weight of 350.6±17.9 kg and age ranging from 24 to 26 months old, were used in this study. The animals were blocked according to the initial body weight (six blocks) and allocated randomly in 12 pens (n = 8 animals per pen), characterizing a completely randomized block design. Pens were considered the experimental unit, and each one of them had 2.5 m of linear bunk space and 213.75 m² (17.1 by 12.5 m). Thus, each animal had an average of 26.76 m² of available area in each pen, as well as 0.31 m of bunk space.

The treatments were randomly assigned to pens, according to blocks, as follows: sodium monensin (25 ppm or 0.0025% of the diet dry matter (DM); SM); sodium monensin (25 ppm or 0.0025% of the diet DM) plus tannins (350 ppm or 0.035% of the diet DM) and saponins (3.92 ppm or 0.000392% of the diet DM; SM+TS). From the beginning to the end of the study, cattle were fed three diets: adaptation, grower, and finisher, which differed only regarding the feed additives that represented the treatments. Experimental diets (Table 1) were formulated to contain the same content of both energy and protein (LRNS; Fox et al., 2004Fox, D. G.; Tedeschi, L. O.; Tylutki, T. P.; Russell, J. B.; Van Amburgh, M. E.; Chase, L. E.; Pell, A. N. and Overton, T. R. 2004. The Cornell Net Carbohydrate and Protein System model for evaluating herd nutrition and nutrient excretion. Animal Feed Science and Technology 112:29-78. https://doi.org/10.1016/j.anifeedsci.2003.10.006
https://doi.org/10.1016/j.anifeedsci.200... ). Cattle received the adaptation diet for the first 19 days of the study, the grower diet was provided from day 20 to day 59, and the finisher diet from day 60 to 98 of the experimental period.

Cattle were fed twice a day (9:00 and 14:00 h), targeting 1 to 2% refusal with free-choice access to a water trough. The dry matter intake (DMI) was calculated daily by weighing the ration offered and refused before the next morning delivery and expressed in kilograms and as a percentage of body weight (BW). Samples of the feed ingredients offered were analyzed weekly for DM, dietary DM was adjusted on a weekly basis according to changes in feed ingredient DM, and water was added to the experimental diets to equalize the DM content in approximately 70%. Feed ingredient samples were dried in a forced-air oven for DM determination (AOAC, 1990AOAC - Association of Official Analytical Chemists. 1990. Official methods of analysis. 15th ed. AOAC, Washington, DC.; method 930.15). The DMI variation was calculated as the difference in intake between two consecutive days throughout the study (Bevans et al., 2005Bevans, D. W.; Beauchemin, K. A.; Schwartzkopf-Genswein, K. S.; McKinnon, J. J. and McAllister, T. A. 2005. Effect of rapid or gradual grain adaptation on subacute acidosis and feed intake by feedlot cattle. Journal of Animal Science 83:1116-1132. https://doi.org/10.2527/2005.8351116x
https://doi.org/10.2527/2005.8351116x... ). Daily DMI variation was expressed as a percentage of variation.

The animals were weighed on days 0, 28, 56, 84, and 98 of the study. All Nellore bulls were withheld from feed for 16 h before the first and last BW assessment. On days 28, 56, and 84, cattle were weighed without fasting, and a 4% discount was adopted to obtain shrunk BW (Stock et al., 1983Stock, R.; Klopfenstein, T.; Brink, D.; Lowry, S.; Rock, D. and Abrams, S. 1983. Impact of weighing procedures and variation in protein degradation rate on measured performance of growing lambs and cattle. Journal of Animal Science 57:1276-1285. https://doi.org/10.2527/jas1983.5751276x
https://doi.org/10.2527/jas1983.5751276x... ). Consequently, average daily gain (ADG) and feed efficiency (ADG/DMI) were calculated at the end of the experiment. Cattle were transported 40 km (~1 h) to a commercial abattoir. Hot carcass weight (HCW) was obtained after kidney, pelvic, and heart fat removal. The dressing percentage was calculated by dividing HCW by the final BW (Pereira et al., 2020Pereira, M. C. S.; Dellaqua, J. V. T.; Sousa, O. A.; Santi, P. F.; Felizari, L. D.; Reis, B. Q.; Pinto, A. C. J.; Bertoldi, G. P.; Silvestre, A. M.; Watanabe, D. H. M.; Estevam, D. D.; Arrigoni, M. D. B. and Millen, D. D. 2020. Feedlot performance, feeding behavior, carcass and rumen morphometrics characteristics of Nellore cattle submitted to strategic diets prior the adaptation period. Livestock Science 234:103985. https://doi.org/10.1016/j.livsci.2020.103985
https://doi.org/10.1016/j.livsci.2020.10... ).

The experimental design was a completely randomized block, and the initial BW was utilized as a criterion for block formation, with the block included as a random effect. Data were analyzed using the PROC MIXED of SAS (Statistical Analysis System, 2003), and all measured response variables were tested for normality (Shapiro-Wilk and Kolmogorov-Smirnov) and heterogeneity of variances (GROUP option of SAS). There was no need for data transformation, as all response variables presented residuals with normal distribution. Similarly, all response variables tested non-significant for heterogeneous variances. Differences between treatments were considered significant when P-values < 0.05.

The statistical analysis for each of the response variables in this study was according to the following statistical model:

in which Y_ij = dependent variable; µ = overall mean of all observations; A_i = effect of additives of order i, in which 1 = SM, 2 = SM+TS; B_j = effect of a block of order j; and E_ij = random residual effect.

3. Results

A significant effect (P = 0.01) was observed for the final BW (day 98), in which cattle consuming diets SM+TS were 10.8 kg heavier than those fed SM (Table 2). Therefore, the addition of tannins and saponins increased the final BW by 2.0%.

A similar response was observed for ADG after 98 days on feed. Adding tannins and saponins to high-concentrate diets containing SM increased ADG (1.96 vs. 1.86 kg) by 5.4%. However, no effect of the addition of tannins and saponins was detected on DMI, expressed in kilograms or percentage of BW (P>0.17). As a result, the addition of tannins and saponins improved the feed conversion of Nellore cattle finished in the feedlot after 98 days on feed (P = 0.01) by 4.3%.

No effect of treatments was detected (P>0.08) on BW, DMI, ADG, and feed conversion on the first 84 days of the study.

Concerning the fluctuation of DMI, cattle consuming SM+TS presented lower variation from 0 to 28 days on feed (P = 0.03); however, no further effects of adding tannins and saponins were detected for the rest of the study.

Finally, the addition of tannins and saponins to high-concentrate diets containing SM did not affect HCW and dressing percentage (P>0.10).

4. Discussion

Research work on the influence of the addition of tannin extracts to the diet of ruminants in recent decades has been quite extensive (Jayanegara et al., 2019Jayanegara, A.; Sujarnoko, T. U. P.; Ridla, M.; Kondo, M. and Kreuzer, M. 2019. Silage quality as influenced by concentration and type of tannins present in the material ensiled: A meta-analysis. Journal of Animal Physiology and Animal Nutrition 103:456-465. https://doi.org/10.1111/jpn.13050
https://doi.org/10.1111/jpn.13050... ). However, the results associated with the addition of tannins in ruminant diets have shown great variability (Yanza et al., 2021 Yanza, Y. R. ; Fitri, A. ; Suwignyo, B. ; Elfahmi ; Hidayatik, N. ; Kumalasari, N. R. ; Irawan, A. and Jayanegara, A. 2021. The utilisation of tannin extract as a dietary additive in ruminant nutrition: A meta-analysis. Animals 11:3317. https://doi.org/10.3390/ani11113317
https://doi.org/10.3390/ani11113317... ), either regarding beneficial or harmful effects on animal health and performance. Nevertheless, in this study, cattle consuming SM+TS showed improved feed conversion, which resulted in an increase of 2.0 and 5.3% in final BW and ADG, respectively.

In a meta-analysis of about 70 studies, Yanza et al. (2021) Yanza, Y. R. ; Fitri, A. ; Suwignyo, B. ; Elfahmi ; Hidayatik, N. ; Kumalasari, N. R. ; Irawan, A. and Jayanegara, A. 2021. The utilisation of tannin extract as a dietary additive in ruminant nutrition: A meta-analysis. Animals 11:3317. https://doi.org/10.3390/ani11113317
https://doi.org/10.3390/ani11113317... observed that the effect of adding condensed tannins to ruminant diets on animal performance is variable as well. A meta-analysis conducted by Orzuna-Orzuna et al. (2021a) reported that dietary supplementation with the addition of tannins at average doses of 14.61 g kg⁻¹ DM did not affect ADG or feed efficiency in beef cattle. The ADG across treatments in this study was 1.91 kg. In general, the ADG of Nellore cattle finished in a feedlot with diets containing similar energy content to the experimental diets offered in this study ranges from 1.2 to 1.60 kg (Zawadzki et al., 2011Zawadzki, F.; Prado, I. N.; Marques, J. A.; Zeoula, L. M.; Rotta, P. P.; Sestari, B. B.; Valero, M. V. and Rivaroli, D. C. 2011. Sodium monensin or propolis extract in the diets of feedlot-finished bulls: Effects on animal performance and carcass characteristics. Journal of Animal and Feed Sciences 20:16-25.; Françozo et al., 2013Françozo, M. C.; Prado, I. N.; Cecato, U.; Valero, M. V.; Zawadzki, F.; Ribeiro, O. L.; Prado, R. M. and Visentainer, J. V. 2013. Growth performance, carcass characteristics and meat quality of finishing bulls fed crude glycerin-supplemented diets. Brazilian Archives of Biology and Technology 56:327-336. https://doi.org/10.1590/S1516-89132013000200019
https://doi.org/10.1590/S1516-8913201300... ). On the other hand, crossbred cattle, involving Nellore and Bos taurus genotypes, may present ADG up to 2.0 kg (Dian et al., 2010Dian, P. H. M.; Prado, I. N.; Valero, M. V.; Rotta, P. P.; Prado, R. M.; Silva, R. R. and Bertipaglia, L. M. A. 2010. Levels of replacing corn by cassava starch on performance and carcass characteristics of bulls finished in feedlot. Semina: Ciências Agrárias 31:497-506. https://doi.org/10.5433/1679-0359.2010v31n2p497
https://doi.org/10.5433/1679-0359.2010v3... ; Fugita et al., 2012Fugita, C. A.; Prado, I. N.; Jobim, C. C.; Zawadzki, F.; Valero, M. V.; Pires, M. C. O.; Prado, R. M. and Françozo, M. C. 2012. Corn silage with and without enzyme-bacteria inoculants on performance, carcass characteristics and meat quality in feedlot finished crossbred bulls. Revista Brasileira de Zootecnia 41:154-163. https://doi.org/10.1590/S1516-35982012000100023
https://doi.org/10.1590/S1516-3598201200... ). Therefore, the performance results obtained in this study are consistent without large variations, which is shown by the SEM of ADG from 0 to 98 days (Table 2).

It is well documented in the literature that tannins possess anti-nutritional factors, causing a reduction in DMI, associated with the astringent taste; however, according to Makkar (2003)Makkar, H. P. S. 2003. Effects and fate of tannins in ruminant animals, adaptation to tannins, and strategies to overcome detrimental effects of feeding tannin-rich feeds. Small Ruminant Research 49:241-256. https://doi.org/10.1016/S0921-4488 (03)00142-1
https://doi.org/10.1016/S0921-4488 (03)0... , the DMI reduction occurs when diet inclusions are above 3%. Therefore, the negative effect of tannins on the DMI of feedlot cattle depends on its concentration in the diet (Jayanegara et al., 2012Jayanegara, A.; Leiber, F. and Kreuzer, M. 2012. Meta analysis of the relationship between dietary tannin level and methane formation in ruminants from in vivo and in vitro experiments. Journal of Animal Physiology and Animal Nutrition 96:365-375. https://doi.org/10.1111/j.1439-0396.2011.01172.x
https://doi.org/10.1111/j.1439-0396.2011... ). Diets containing low (0.5-3.0%) tannin concentration do not affect feed intake (Piñeiro-Vázquez et al., 2018Piñeiro-Vázquez, A. T.; Jiménez-Ferrer, G.; Alayon-Gamboa, J. A.; Chay-Canul, A. J.; Ayala-Burgos, A. J.; Aguilar-Pérez, C. F. and Ku-Vera, J. C. 2018. Effects of quebracho tannin extract on intake, digestibility, rumen fermentation, and methane production in crossbred heifers fed low-quality tropical grass. Tropical Animal Health and Production 50:29-36. https://doi.org/10.1007/s11250-017-1396-3
https://doi.org/10.1007/s11250-017-1396-... ). It has been reported that doses of tannins higher than 0.5% of diet DM may decrease the rate of nutrient digestion in the rumen (Mueller‐Harvey, 2006). In contrast, some studies have reported a non-harmful effect of tannin extract on ruminant intake (Al-Kindi et al., 2016 Al-Kindi, A. ; Schlecht, E. ; Schiborra, A. and Joergensen, R. G. 2016. Effects of quebracho tannin extract ( Schinopsis balansae ) and activated charcoal on feed intake and digestibility by goats and their faecal microbial biomass. Biological Agriculture & Horticulture 32:159-169. https://doi.org/10.1080/01448765.2015.1108869
https://doi.org/10.1080/01448765.2015.11... ; Santos et al., 2012Santos, W. B. R.; Santos, G. T.; Neves, C. A.; Marchi, F. E.; Kazama, D. C. S.; Ítavo, L. C. V.; Damasceno, J. C. and Petit, H. V. 2012. Rumen fermentation and nutrient flow to the omasum in Holstein cows fed extruded canola seeds treated with or without lignosulfonate. Revista Brasileira de Zootecnia 41:1747-1755. https://doi.org/10.1590/S1516-35982012000700026
https://doi.org/10.1590/S1516-3598201200... ). In this study, we decided to use a dose of condensed tannins that is approximately ten times lower than the usual doses reported in most studies in the literature to minimize further negative effects, mainly on DMI and ruminal deamination, which are also effects promoted by sodium monensin (Duffield et al., 2012Duffield, T. F.; Merrill, J. K. and Bagg, R. N. 2012. Meta-analysis of the effects of monensin in beef cattle on feed efficiency, body weight gain, and dry matter intake. Journal of Animal Science 90:4583-4592. https://doi.org/10.2527/jas.2011-5018
https://doi.org/10.2527/jas.2011-5018... ). Tannins were included at 0.035% of the diet (DM basis), which did not negatively affect DMI (Table 2) and may explain the improved feed conversion that resulted in a positive effect on ADG, since negative effects on intake and on nutrient digestion may have been absent. Furthermore, in this study, DMI can be considered high for feedlot Nellore cattle (11.5 kg/day or 2.5% of BW across treatments), although feed intake was ad libitum. In general, DMI ranges from 2.0 and 2.3% of BW in diets containing similar energy content (Ornaghi et al., 2017Ornaghi, M. G.; Passetti, R. A. C.; Torrecilhas, J. A.; Mottin, C.; Vital, A. C. P.; Guerrero, A; Sañudo, C.; Campo, M. M. and Prado, I. N. 2017. Essential oils in the diet of young bulls: Effect on animal performance, digestibility, temperament, feeding behaviour and carcass characteristics. Animal Feed Science and Technology 234:274-283. https://doi.org/10.1016/j.anifeedsci.2017.10.008
https://doi.org/10.1016/j.anifeedsci.201... ; Souza et al., 2019Souza, K. A.; Monteschio, J. O.; Mottin, C.; Ramos, T. R.; Pinto, L. A. M.; Eiras, C. E.; Guerrero, A. and Prado, I. N. 2019. Effects of diet supplementation with clove and rosemary essential oils and protected oils (eugenol, thymol and vanillin) on animal performance, carcass characteristics, digestibility, and ingestive behavior activities for Nellore heifers finished in feedlot. Livestock Science 220:190-195. https://doi.org/10.1016/j.livsci.2018.12.026
https://doi.org/10.1016/j.livsci.2018.12... ; Carvalho et al., 2021Carvalho, V. M.; Ávila, V. A. D.; Bonin, E.; Matos, A. M.; Prado, R. M.; Castilho, R. A.; Silva, R. R.; Abreu Filho, B. A. and Prado, I. N. 2021. Effect of extracts from baccharis, tamarind, cashew nut shell liquid and clove on animal performance, feed efficiency, digestibility, rumen fermentation and feeding behavior of bulls finished in feedlot. Livestock Science 244:104361. https://doi.org/10.1016/j.livsci.2020.104361
https://doi.org/10.1016/j.livsci.2020.10... ).

The addition of condensed tannins and saponins positively affected the fluctuation of DMI in the first 28 days of the study, which is an indication that feedlot diets containing SM+TS may promote a more consistent protective effect against ruminal acidification. This phenomenon may partially explain the feed conversion improvement obtained in this study when SM was associated with tannins and saponins.

Moreover, the addition of tannins and saponins to the feedlot diets may have benefited the Nellore bulls used in this study; because of their mature weight about 560 kg (Fox et al., 1992Fox, D. G.; Sniffen, C. J.; O'Connor, J. D.; Russell, J. B. and Van Soest, P. J. 1992. A net carbohydrate and protein system for evaluating cattle diets: III. Cattle requirements and diet adequacy. Journal of Animal Science 70:3578-3596. https://doi.org/10.2527/1992.70113578x
https://doi.org/10.2527/1992.70113578x... ), the aminoacids requirements are still high (NASEM, 2016NASEM - National Academies of Science, Engineering and Medicine. 2016. Triennial review of the national nanotechnology initiative. National Academies Press, Washington, DC.), and tannins, by binding to dietary proteins in the rumen, may have increased the flow of aminoacids to the intestines (Huang et al., 2018Huang, Q.; Liu, X.; Zhao, G.; Hu, T. and Wang, Y. 2018. Potential and challenges of tannins as an alternative to in-feed antibiotics for farm animal production. Animal Nutrition 4:137-150. https://doi.org/10.1016/j.aninu.2017.09.004
https://doi.org/10.1016/j.aninu.2017.09.... ). As a result, this may explain the lack of effect on HCW and dressing percentage by adding tannins and saponins to feedlot diets containing SM, since it would be more pronounced in a subsequent phase that greater carcass fat deposition is expected (Owens et al., 1995Owens, F. N.; Gill, D. R.; Secrist, D. S. and Coleman, S. W. 1995. Review of some aspects of growth and development of feedlot cattle. Journal of Animal Science 73:3152-3172. https://doi.org/10.2527/1995.73103152x
https://doi.org/10.2527/1995.73103152x... ). Unfortunately, measures of rib-eye area and fat thickness were not taken in this study.

Saponins manage to inhibit the growth of gram-positive bacteria of the rumen flora, due to the similar action of ionophores, altering the surface tension of the extracellular matrix (Cheeke, 2000Cheeke, P. R. 2000. Actual and potential applications of Yucca schidigera and Quillaja saponaria saponins in human and animal nutrition. p.241-254. In: Oleszek, W. and Marston, A. (eds). Saponins in food, feedstuffs and medicinal plants. Proceedings of the Phythochemical Society of Europe, vol. 45. Springer, Dordrecht. https://doi.org/10.1007/978-94-015-9339-7_25
https://doi.org/10.1007/978-94-015-9339-... ). Lila et al. (2003)Lila, Z. A.; Mohammed, N.; Kanda, S.; Kamada, T. and Itabashi, H. 2003. Effect of sarsaponin on ruminal fermentation with particular reference to methane production in vitro. Journal of Dairy Science 86:3330-3336. https://doi.org/10.3168/jds.S0022-0302 (03)73935-6
https://doi.org/10.3168/jds.S0022-0302 (... observed that the addition of saponins stimulated fermentation, as the production of volatile fatty acids increased proportionally to the increase in saponin addition. Goel et al. (2008)Goel, G.; Makkar, H. P. S. and Becker, K. 2008. Changes in microbial community structure, methanogenesis and rumen fermentation in response to saponin-rich fractions from different plant materials. Journal of Applied Microbiology 105:770-777. https://doi.org/10.1111/j.1365-2672.2008.03818.x
https://doi.org/10.1111/j.1365-2672.2008... concluded that the addition of saponins has the potential to increase the efficiency of rumen fermentation. The addition of saponins to the diet does not influence digestibility in the rest of the digestive system, being limited to effects in the rumen (Wina et al., 2005Wina, E.; Muetzel, S. and Becker, K. 2005. The impact of saponins or saponin-containing plant materials on ruminant production: a review. Journal of Agricultural and Food Chemistry 53:8093-8105. https://doi.org/10.1021/jf048053d
https://doi.org/10.1021/jf048053d... ). Somehow, saponins may have positively interacted with tannins and monensin to improve ruminal fermentation; however, the magnitude of the effect of saponins in the rumen associated with monensin and tannins is still unknown and deserves further investigation.

The dose of condensed tannins used in this study is approximately ten times lower than the doses used in most studies in the literature, in addition to being associated with saponins. However, it is not possible to infer in this study that tannins alone, or their association with saponins, without sodium monensin, contributed to the positive responses observed. Therefore, further studies are needed to better understand the effects of a lower dose of condensed tannins associated with saponins.

5. Conclusions

The addition of tannins and saponins to high-concentrate diets interacts positively with sodium monensin by improving the feedlot performance of Nellore cattle. Thus, the use of saponins and condensed tannins, at a dose 10 times lower than usually practiced, associated with sodium monensin, may be an alternative to feedlot cattle operations, especially those that sell cattle on a body weight basis.

Edited by

Publication Dates

History