PSIX-10 The replacement of corn by soybean molasses improves ruminal environment of feedlot sheep

Abstract

The goal of this study was to assess the effects of increasing levels of soybean molasses (SM) on ruminal parameters of feedlot sheep. Nine crossbred ruminally-cannulated male sheep (73.3 ± 2.5 kg BW) were randomly distributed in a triple 3 × 3 Latin square design. The treatments consisted of isonitrogenous (18% CP) and isoenergetic (2.7 Mcal/kg) diets, containing 0, 15 or 30% SM (DM basis). After 14 d of adaptation period, rumen fluid samples were collected in each experimental period, at 0, 2, 4, 6, 8 and 10 h after feeding, to evaluate ruminal pH, NH3-N and VFA concentrations. The pH was measured immediately after rumen fluid sampling, and NH3-N concentrations were determined with micro-Kjeldahl apparatus. The concentration of VFA was assessed by gas chromatography. Data were evaluated using the MIXED procedure of SAS, with repeated measures over time. Orthogonal contrasts were used to determine the linear and quadratic effects of SM inclusions, as well as the contrast Control × SM treatments. There was no interaction of time of sampling × treatment for all variables evaluated (P > 0.05). The inclusion of SM increased linearly (P = 0.02) the ruminal pH (5.92 to 5.21 – 0 and 30%, respectively), and decreased linearly (P = 0.006) the NH3-N concentration (32.19 to 21.78 mg/dL – 0 and 30%, respectively). The addition of SM did not alter most of VFA, with exception for valeric acid (quadratic, P = 0.05), with the higher value observed in 15% SM-fed animals (1.33 mMol/L). However, when the percentage of each VFA was evaluated, the inclusion of SM increased linearly the butyric acid (P = 0.05), from 14.1 to 16.9%. The results indicate that the inclusion of soybean molasses at up to 30% (DM basis) improves the ruminal fermentation of diets in feedlot crossbred sheep.

Soybean molasses increases subcutaneous fat deposition while reducing lipid oxidation in the meat of castrated lambs

“…On the hand, the lower fiber content in the SM20 diet did not seem to affect ruminal pH, as indicated by the higher muscle content of stearic acid (C18:0), the content of which is narrowly linked to biohydrogenation in the rumen ( Santos-Silva et al, 2016 ). Agreeing with this, SM inclusion up to 30% in the diet of adult sheep directly increased ruminal pH ( Pereira-Junior et al, 2019 ). Another indicatives of good ruminal biohydrogenation capacity are the similar levels of PUFA and higher amounts of SFA and some MUFA in the muscle of SM20 lambs, despite the presence of 45% and 51% of PUFA in CON and SM20 diets, respectively.…”

“…The high solubility of soluble carbohydrates in SM allows for easy escape of microbial fermentation, resulting in the conversion of protein and non-protein nitrogen into ammonia in the rumen, and this, in turn, into urea by the liver ( Hailemariam et al, 2021 ). Pereira-Junior et al (2019) , when evaluating inclusions of up to 30% of SM in DM, found a reduction in ruminal NH 3 , indicating greater epithelial absorption. In turn, our current study found higher levels of urea in the blood, indicating high activity in the urea cycle.…”

“…However, in the current study, this does not appear to be the reason for the greater fat deposition in this tissue. Previous studies have shown that replacing corn by SM does not seem to lead to modifications in the profile of short-chain fatty acids when considering inclusions of up to 20% ( Almeida et al, 2018 ) and 30% SM in the diet ( Pereira-Junior et al, 2019 ). The current study did not focus on analyzing in detail the lipid metabolism in subcutaneous tissue though, thus not allowing us to infer how SM affected fat deposition and highlighting the need for further research seeking to elucidate the underpinning mechanisms.…”

“…The inclusion of soybean molasses ( SM ) in diets with a high starch content may represent an alternative to mitigate the aforementioned metabolic problems. For instance, previous studies have observed that the replacement of starch with SM provided greater stability in ruminal pH ( Pereira-Junior et al, 2019 ). This can be explained by the large amount of soluble carbohydrates present in SM (e.g., sucrose and fructose), which can lead to a higher influx of simple sugars into the intestine as they are readily solubilized in water.…”

Soybean Molasses in Animal Nutrition

“…Moreover, feed digestibility, feed consumption behavior, and metabolic profile of sheep were not affected, indicating that soybean molasses can be used successfully as a feed ingredient for sheep until 12% of the daily ration without any risk of intoxication. The influence of soybean molasses on the ruminal environment has been also investigated [ 67 , 68 , 69 , 70 , 71 ]. Sheep diet containing 0%, 15%, or 30% soybean molasses (dry matter basis) increased proportionally ruminal pH and decreased NH3-N concentration, thereby improving the ruminal fermentation.…”