Effect of sorghum tannins in sheep fed with high-concentrate diets

Abstract

The aim of this study was to evaluate the nutritional value of three sorghum cultivars with different concentrations of condensed tannins in sheep diets. Six adult sheep (LW=56kg) with rumen and duodenal fistulas were assigned to experimental groups using two 3x3 Latin Square designs. The diets were formulated using three sorghum cultivars: LTC (low-tannin cultivar), MTC (medium-tannin cultivar) and HTC (hightannin cultivar). Microbial nitrogen (MN) concentration in the duodenum was measured using a 15 N trace technique. LTC, MTC and HTC diets presented values of 788, 722 and 747 (SE=20.6) g kg -1 for dry matter digestibility and 633, 535 and 530 (SE=35.8) g/kg for crude protein digestibility. The LTC diet was significantly different from the other diets (P<0.05). The nitrogen balance was 145.5, 94.8 and 83.8g kg -1 (SE=13.0) for LTC, MTC and HTC, respectively, with LTC showing greater nitrogen retention (P<0.05). Values obtained for MN in the digesta were 301, 364 and 469 (SE=30.6) g kg -1 for LTC, MTC and HTC, respectively, and there was no statistical difference (P>0.05) between the diets. The presence of condensed tannins in the sorghum interfered with the sheep's nitrogen retention; however, the microbial protein supply to the duodenum of the animals was not inhibited.Keywords: feed evaluation; microbial protein; nitrogen balance; rumen  de 145,5; 94,8 e 83,0) RESUMO O objetivo do presente estudo foi avaliar o valor nutricional de três cultivares de sorgo com diferentes concentrações de tanino condensado em dietas de ovinos. Seis carneiros machos, adultos, castrados, canulados no rúmen e duodeno foram divididos em três grupos experimentais, em um delineamento em quadrado latino 3x3. Os tratamentos foram representados por três dietas experimentais contendo diferentes cultivares de grão de sorgo: LTC (cultivar com baixa concentração de tanino), MTC (cultivar com concentração média de tanino) e HTC (cultivar com concentração alta de tanino). As concentrações de nitrogênio de origem microbiana no duodeno (MN) foram mensuradas pela técnica de marcador isótopo estável 15N. As dietas LTC, MTC e HTC apresentaram valores de 788, 722 e 747g.kg-1 (EP=20,6) para a digestibilidade aparente da matéria seca e 633, 535 e 530g.kg-1 (EP=35,8) para a digestibilidade aparente da proteína bruta. A dieta LTC apresentou diferença significativa quando comparada às demais dietas para as avaliações de digestibilidade (P<0,05). Os valores encontrados para o balanço de nitrogênio foram

Effects of corn replacement by sorghum in diets on performance, nutrient utilization, blood parameters, antioxidant status, and meat colour stability in lambs

“…The present study did not find significant effect on DM digestibility, but N excretion was increased in feces and apparent CP digestibility was decreased with increasing sorghum levels. The lower digestibility of CP might be explained by the following three reasons: (i) the N intake for S treatment is higher compared with C treatment; (ii) tannins in sorghum interfere with protein digestion period, Cabral et al (2013) evaluated the nutritional values of three sorghum cultivars with different concentrations of condensed tannins in sheep diets, and found that protein digestibility was reduced with the increase of tannin content in sorghum; (iii) the structure of sorghum could decrease the digestibility of protein and starch owing to the encasement of starch granules in a protective protein matrix inside the hard peripheral endosperm layer of the grain (Rooney and Pflugfelder 1986).…”

Tannin in Ruminant Nutrition: Review

“…The voluntary feed intake of ruminants by providing plants with high condensed tannin (CT) content (usually >50 g/kg DM) can be reduced, with a moderate or low intake (<50g/kg DM) not affecting it [ 131 ]. On this side, Cabral Filho et al [ 132 ] observed no effect on DM consumption of sheep.…”

“…Ruminal pH changes affect the complexes and provide information about the function of tannins in the gastrointestinal tract [ 103 ]. Cabral Filho et al [ 132 ] investigated three levels of tannin in the diet of sheep and reported a different DM digestibility between high- and low-tannin cultivars. The low tannin content diet had a higher crude protein digestibility, and there were no significant differences between the medium tannin content and high tannin content diets.…”

“…Cabral Filho et al [ 132 ] observed no significant differences between the treatment groups with diets containing three different concentrations of tannin. Aboagye, Oba, Castillo, Koenig, Iwaasa and Beauchemin [ 10 ] have shown that the combination of HT and condensed tannin at 1.5% dietary DM also tended to reduce CH4 emissions without adverse effects on performance.…”

Mesquite (Prosopis juliflora) extract as a phytogenic additive for sheep finished on pasture in the semiarid region

“…One of the representatives of such products, of interest for production, is tannin, one of the secondary metabolites of plants. This compound is not involved in processes considered essential for plants (Cabral Filho et al, 2013). Tannins improve digestibility of nutrients, optimizing production of propionic acid, microbial protein synthesis and reduce the number of ciliate protozoa (Castro-Montoya et al, 2011;Alves Júnior et al, 2017).…”