The effect of tannin addition to turnip forage silage (lenox/brassica rapa L.) on silage fermentation and in vitro digestibility

This study was conducted to investigate the effects of forage turnip (lenox/Brassica rapa L.) plant ensiled at two different dry matter levels, with two different concentrations of tannin (50 and 75 g/kg/KM) and opening on different days (2, 7, and 90th days) on the crude nutrients, fermentation, and in vitro digestibility values of the silage. The silage material of the study consisted of forage turnip (lenox/Brassica rapa L.) harvested during the full encapsulation period of the flowering period. Forage turnip was ensiled at two different dry matter levels (20% and 35%); one without added tannin, without additives, and the other two with different concentrations of tannin (50 and 75 g/kg/KM). Silos were prepared in 1-liter leak-proof, airtight, plastic jars according to the 2x3x3 factorial experimental design with 3 replications. Samples were taken from the prepared silos by opening them on three different days (2, 7 and 90 days). Crude nutrient, fermentation quality and in vitro organic matter digestibility analyses were applied to the samples taken from the prepared silages. For raw nutrient analyses; dry matter (DM), crude ash (HK), crude fat (HY), crude protein (HP), crude cellulose (HS), neutral detergent insoluble fiber (NDF), acid detergent insoluble fiber (ADF), acid detergent insoluble lignin (ADL) analyses were performed and nitrogen-free extract matter (NÖM), hemicellulose (HC), cellulose (C), metabolic energy calculations were performed. In fermentation analyses; total aerobic mesophilic bacteria (TMAB), total lactic acid bacteria (TLAB), yeast mold (MK) count, pH, water-soluble carbohydrate (WCC), organic acid (UYA), free ammonia nitrogen (NH3-N) tests were performed. Aerobic stability (AS) and total aflatoxin (B1+B2+G1+G2) analyses were performed only on the 90th day samples. In vitro organic matter digestibility analyses were also performed on the samples. According to the results obtained from the study; 50 or 75g tannin addition to the silage material at 20 and 35% dry matter levels was found to be effective in dry matter preservation compared to the groups without tannin addition (p<0.05). On the 90th day of the study (in samples G3, 6, 9, 12, 15 and 18), it was determined that the desired pH values were provided in legume silages. Despite the high protein and water content of the silage material, the desired pH decrease was achieved as a result of the good compression process. It was determined that the pH decrease in the tannin added groups (G6, 9 and 15, 18) was lower than the groups without tannin (p<0.001). WSC and NH3-N findings of the silage materials were found to be less in the 35% DM groups with withering process than in the 20% DM groups (p<0.001). In addition, lower values were observed for the NH3-N parameter at 20% and 35% DM levels in 50 and 75 g tannin added groups compared to the groups without tannin addition (p<0.05). For the organic acid findings of the study; LA and AA values were determined to be higher in 35% dry matter level groups compared to 20% dry matter groups (p<0.001). Within the tannin added groups; 75 g groups produced more LA compared to 50 g added experimental groups, and both added groups produced more LA compared to the groups without tannin addition (p<0.05). In the 2nd day samples of the silage materials, lower BA levels were found in 35% DM groups compared to 20% DM groups (p<0.05). In TAMB and TLAB plantings carried out in silage materials, higher reproduction was determined at 35% dry matter level compared to 20% dry matter level (p<0.001). On the 90th day samples, higher TLAB growth was found in 50 and 75 g tannin added groups compared to the groups without tannin (p<0.001) at both dry matter levels. In the aerobic stability analysis performed on 18 samples taken on the 90th day of silo opening of the study, less CO2 production occurred at 35% DM level compared to 20% DM level (p<0.001). In addition, lower CO2 production was determined in the 50 and 75 g tannin added groups compared to the groups without tannin (p<0.001). No aflatoxin (B1+B2+G1+G2) was found in any of the 18 samples taken from the 90th day of silo opening. In the IVOMS analysis, higher values were determined in the groups with 35% DM level compared to the 20% DM groups (p<0.001). On the other hand, it was observed that IVOMS values decreased on the days when silage fermentation progressed (p<0.05). According to the results obtained from the study; it was determined that the fodder turnip (lenox/Brassica rapa L.) plant would provide better fermentation quality when it was ensiled at 35% dry matter levels by applying a proper withering process. In addition, it was found that when sufficient compression was applied during the ensiling process, sufficient LA production was achieved even at the harvested dry matter level of the plant and the pH value decreased. It was determined that this situation could prevent mycotoxin production even without the contribution. It was observed that the 50 and 75 g tannin addition encouraged TLAB reproduction, produced higher LA and therefore lower pH values were obtained compared to the groups without tannin addition at 20 and 35% KM values due to its antioxidant effects. It was determined that due to these antioxidant effects of tannins, lower CO2 production occurred in the tannin-applied groups and this situation increased the aerobic stability value. In the light of these data, it is thought that tannin additives may be beneficial in extending the shelf life of silos, that fodder turnip silage generally exhibits quality silage properties, and that it can be an alternative roughage for cattle and sheep farming.