Soybean hulls as feed substitute of ground corn can increase the fiber digestibility and bacterial fibrolytic profile of grazing Nellore steers during the rainy season

Abstract

Soybean hulls as feed substitute of ground corn can increase the fiber digestibility and bacterial fibrolytic profile of grazing Nellore steers during the rainy season Casca de soja como substituto do milho moído pode aumentar a digestibilidade da fibra e o perfil fibrolítico bacteriano de novilhos Nelore em pastejo durante a estação chuvosa AbstractThis study aimed to evaluate the effect of replacement of ground corn by soybean hulls associated or not to whole soybean grain in the feed supplement on intake, nutrient digestibility, rumen microbial population, and fermentation parameters of growing Nellore steers grazing Brachiaria brizantha cv. Xaraés during rainy season. Were used eight castrated Nellore steers (425 ± 36 kg of body weight (BW)) fitted with ruminal and duodenal cannulas in a replicated 4 × 4 Latin square with a 2 × 2 factorial arrangement, allocated into 4 paddocks of 0.25 ha each, consisting of Brachiaria brizantha cv. Xaraés and supplemented with: (1) ground corn combined with whole soybean grain (SG); (2) ground corn without SG; (3) soybean hulls (SH) combined with SG; and (4) SH without SG. Supplement intake was no affected by SG or SH (mean 2.12 kg -1 d, P > 0.05). There were no interactions between SH and SG on DM and nutrients intake (P > 0.05). The addition of SG reduced the dry matter (DM) intake expressed as % of BW and Kg -1 d, as well forage DM, organic matter (OM), crude protein (CP), neutral detergent fiber (aNDF), and gross energy (GE) intake (P ≤ 0.01). Animals supplemented with SH without SG had greater digestibility of DM (74.52), OM (77.62), CP (77.51), NDF (71.93) and GE (72.90) than animals supplemented with SH with SG (DM =69.01, OM = 71.92, CP = 72.81, NDF = 66.01, GE =68.01) expressed as % (P ≤ 0.01). The addition of SG in the supplements declined the ruminal pH and NH 3 -N (P=0.02). Animals supplemented without SH without SG showed greater Entodinium counts (6.01 n x 10 4 ml -1 , P=0.04), and SG supplementation decreased the numbers of Dasytricha, Isotricha, and ruminal total protozoa (P < 0.01). The abundance of Ruminococcus albus, R. flavefaciens, and Archaeas were higher for SH without SG supplement. Additionally, animals supplemented with SG had lower numbers of Fibrobacter succinogenes. The use of soybean hulls without whole soybean grain in the supplement may be effective to increase fiber digestibility, N retained, R. albus and R. flavefaciens in the rumen of Nellore steers grazing Brachiaria brizantha cv. Xaraés during the rainy season. Resumo Este estudo avaliou o efeito da substituição do milho moído por casca de soja associado ou não a grãos de soja no suplemento de novilhos Nelore em crescimento pastejando Brachiaria brizantha cv. Xaraés durante a estação chuvosa sobre o consumo, digestibilidade de nutrientes, população microbiana ruminal, e parâmetros de fermentação de novilhos Nelore (425 ± 36 kg de peso corporal (PC)) em crescimento pastejando Brachiaria brizantha cv. Xaraés durante a estação chuvosa. Foram utilizados oito novilhos Nelore com cânulas no rúm...

Digestive Potential of Soybean Agro-Industry Byproducts

“…The greater amount of the NPN fraction added to the lesser amount of A + B1 of the carbohydrate fraction caused by the inclusion of soybean hulls means that the rumen pH does not decrease abruptly (Table 3), thus maintaining a rumen environment that favors the growth of fibrolytic bacteria, resulting in greater NDF degradability (Table 4) and confirming earlier reports [22].…”

“…The inclusion of soybean hulls caused an increase in fraction C, but the lignin in these soybean hulls had characteristics of lower complexation with cellulose and thus these interactions can cause a greater amount of degraded cellulose. This can be seen in Table 4, where the addition of the soybean hulls caused a reduction in fraction I in the DM and CP as well as a reduction of INDF [22].…”

“…The increase in NPN fraction improved the forage quality because to meet the nutritional requirements of the rumen, microorganisms provide a nitrogen source so that ruminal bacteria can build their proteins and thus increase the growth and replication of the microrganisms that cause an increase in the efficiency of digestive processes with a greater use of fractions of slow degradation by increasing the supply of microorganisms present in the rumen [22,23].…”

“…This greater degradability was associated with a higher amount of CP with the inclusion of soybean hulls, increasing the availability of nitrogen, which increased DM degradability by providing a greater number of added fibrolytic bacteria. Additionally, the lower lignin and cellulose binding complexity of soybean hulls caused a lower amount of fraction I in DM degradability, which can impact DM intake and the amount of energy available for the rumen microorganisms after digestion [22,24].…”

Soybean hulls inclusion on silage of wet brewery waste

“…The soybean hulls present a low lignin content and large proportion of potentially digestible fiber, being very used as primary ingredient in ruminant diets. Many studies have demonstrated the advantages of using soybean hulls as an energy source for ruminants in replacement of corn, as long as it is supplied together with effective fiber sources to reduce the rate of passage and enable ruminant fermentation (Bastos et al, 2015;José Neto et al, 2017;José Neto et al, 2019). Replaces the corn of the ruminant diet with soybean hulls, without changing the quality of animal performance, requires an order of 75%, better digestibility and energy value of the diet, maintaining in certain occasions the economic viability (Alcalde et al, 2009;Gentil et al, 2011).…”