Resumo
aguardando
Three experiments were carried out to examine the effect of lignocellulolytic enzymes on the nutritive value of whole-plant corn silage (WPCS). In experiment 1, we examined the effect of spent substrate from Pleurotus ostreatus cultivation (SSPO) on the chemical composition, antioxidant capacity, lignin monomers, and in vitro 5 digestibility of WPCS. In experiment 2, we evaluated the performance of lactating goats fed WPCS treated with different levels of SSPO. In experiment 3, we verified the activity of an enzymatic complex at different pH and the effects of adding increasing levels of that enzymatic complex produced by Pleurotus ostreatus on the fermentative profile, chemical composition, and ruminal digestibility along of the days on the onset of fermentation of WPCS. In experiment 1, four levels of lignocellulolytic enzymes from spent substrate of Pleurotus ostreatus were tested in a completely randomized design: 0, 10, 20, and 30 mg of lignocellulosic enzymes/kg of fresh matter, and four replicates per treatment (vacuum-sealed bags). The bags were opened 60 d after ensiling. The NDF, ADF, lignin, and cellulose concentration decreased quadratically. At the nadir point, SSPO decreased NDF by 14.1%, ADF by 19.5%, lignin by 9.07%, and cellulose by 22.1% compared to the untreated silage. Therefore, SSPO led to a quadratic increase in IVDMD of WPCS (+10.3 % at vertex). In experiment 2, WPCS treated with three enzyme levels (0, 10, or 30 mg/kg fresh matter, chosen based on experiment 1) were fed to lactating goats as part of TMR. Nine lactating Saanen goats (62.68±7.62 kg BW; 44±8 days in milk; 2.91±0.81 kg of milk/day, mean±SD) were assigned to three 3 × 3 Latin squares. Intake and digestibility of dry matter and nutrients, microbial protein syntheses, and milk production and composition were examined. The SSPO increase the in vivo total-tract ADF digestibility quadratically. Additionally, the concentration of polyphenols in milk increased linearly with the addition of SSPO in WPCS; however, no other differences were detected among treatments. In experiment 3, the lignocellulolytic enzymatic complex was obtained through in vitro cultivation of Pleurotus ostreatus, and the activities of laccase, lignin peroxidase, manganese peroxidase, endo and exoglucanase, xylanase, and mannanase were determined at pH 3, 29 4, 5, and 6. Following, five different enzymatic complex levels were tested in a completely randomized block design: 0; 9; 18; 27, and 36 mg of lignocellulosic enzymes/kg of fresh matter (FM) of whole-plant corn, with four replicates per treatment (vacuum-sealed bags). The bags were opened after 1, 2, 3, and 7 d of ensiling to evaluate the onset of fermentation and after 30 d of storage to evaluate the fermentation, chemical composition, and in situ digestibility of WPCS. Laccase showed highest activity at pH 5 (P < 0.01), whereas manganese peroxidase and lignin peroxidase had a higher activity at pH 4 (P < 0.01;< 0.01, respectively). There was no interaction between the enzymatic complex and days of fermentation (P > 0.11). The concentration of WSC decreased quadratically at the onset of fermentation (P = 0.02) due to its consumption that led to a quadratic increase of lactic acid (P = 0.01) and a linear increase of acetic acid (P = 0.02). As a result of increasing those organic acid concentrations, pH decreased quadratically (P = 0.01). Lignin concentration decreased linearly (P = 0.04) with the enzymatic complex at 30 d of storage. The collective interpretation of these results leads to the conclusion that 10 mg of lignocellulolytic enzymes from SSPO per kg of FM of WPC presented the best effect in silage production due to more evident reduction in NDF, ADF, and lignin concentration and increased ADF digestibility of lactation goats
Resumo
Objetivou-se avaliar o efeito da adição de óleo de linhaça e/ou da vitamina E sobre o consumo de matéria seca, digestibilidade dos nutrientes, antioxidantes e estabilidade oxidativa no sangue e no leite e perfil lipídico do leite de búfalas em lactação. Foram utilizadas quatro fêmeas bubalinas mestiças, após o pico de lactação (97±22 dias de lactação), com peso corporal médio de 655±37 kg, submetidas a uma ordenha diária com presença do bezerro, distribuídas em um quadrado latino 4x4, em esquema fatorial 2x2 (óleo: presença e ausência; e vitamina E: presença e ausência). Assim, foram compostas as dietas experimentais: controle (ausência de óleo e vitamina); dieta com óleo de linhaça, 25 g/kg MS; dieta com vitamina E, 375 UI/kg MS; dieta com óleo (25 g/kg MS) e com vitamina E (375 UI/kg MS). O óleo foi pesado juntamente com o concentrado, enquanto a vitamina E foi fornecida em uma porção de aproximadamente 50g da ração total misturada, após a ingestão total dessa parcela o restante da alimentação foi fornecida. O consumo e os parâmetros sanguíneos não tiveram efeitos (P>0,05) da adição de óleo de linhaça e/ou da vitamina E. Entretanto, a adição de óleo reduziu (P<0,01) a digestibilidade da fibra em detergente neutro, aumentou a do extrato etéreo (P<0,01) e aumentou (P<0,05) a produção e a densidade do leite e também o TBARS e dieno conjugado. Ainda, ocasionou tendência de aumento dos ácidos graxos (AG) de cadeia longa (P=0,06), aumentos (P<0,05) dos AG de cadeia média, de cadeia curta e dos poli-insaturados, concentração de n-3 e reduziu a razão n-6/n-3 (P=0,01) no leite, a atividade da enzima 9-dessaturase (P=0,01), a concentração de gordura do leite (P=0,04) e tendência de redução de sólidos totais (P=0,08). A vitamina E causou aumentos na digestibilidade da fração fibrosa (P<0,05), no poder redutor do leite (P=0,01), na atividade da enzima 9-dessaturase, na capacidade antioxidante total no sangue (P=0,10) e reduziu a produção de TBARS (P=0,02). A interação entre o óleo e a vitamina E promoveu tendência de aumentos da capacidade antioxidante total (P=0,07) e do poder redutor do leite (P=0,07). Tanto a adição do óleo quanto da vitamina E reduziram os índices de trombogenicidade e aterogenicidade. Associando a fonte lipídica com a vitamina E, é possível obter uma melhora da atividade antioxidantes no organismo das búfalas, assim como obter perfil lipídico melhorado e com boa estabilidade oxidativa em leite de búfalas
The objective of this study was to evaluate the effect of the addition of flaxseed oil and/or vitamin E on DM (dry matter) intake, nutrient digestibility, antioxidants and oxidative stability in blood and milk and milk lipid profile of lactating buffaloes. Four crossbred buffalo females were used, after the peak of lactation (97±22 days of lactation), mean body weight of 655±37 kg submitted to a daily milking with the presence of the calf, distributed in a 4x4 Latin square design, in a 2x2 factorial arrangement (Oil: presence and absence, and vitamin E: presence and absence). This is how the experimental diets were composed: control (absence of oil and vitamin); Diet with flaxseed oil, 25 g/kg DM; Diet with vitamin E, 375 IU/kg DM; Diet with flaxseed oil (25 g/kg DM) and vitamin E (375 IU/kg DM). The oil was weighed together with the concentrate, while vitamin E was supplied in a portion of approximately 50 g of the total mixed feed, after the total intake of that portion the rest of the feed was provided. The intake of ethereal extract increased and non-fibrous carbohydrates reduced in the diets with flaxseed oil. Blood parameters had no effect (P>0.05) on the addition of flaxssed oil and/or vitamin E. However, the addition of oil reduced the digestibility of neutral detergent fiber (P<0.01), increased digestibility of ethereal extract (P<0.01) and increased (P<0.05) milk production and density, as well as TBARS and conjugated diene. In addition, there was a tendency for long chain fatty acids (FA) to increase (P=0.06), increases (P<0.05) in medium chain FA, short chain and polyunsatured, n-3 concentration and reduced the n-6/n-3 ratio in the milk and the activity of the enzyme 9-desaturase (P=0.01), milk fat concentration (P=0.04) and tendency to reduce the total solids (P=0.08). Vitamin E increased the digestibility of the fibrous fraction (P<0.05), the milk reducing power (P=0.01), the 9-desaturase enzyme activity, the total antioxidant capacity in the blood (P=0.10) and reduced the production of TBARS (P=0.02). The interaction of the oil and the vitamin E promoted a tendency of increases in total antioxidant capacity (P=0.07) and milk reducing power (P=0.07). Both the addition of the oil and vitamin E reduced the rates of thrombogenicity and atherogenicity. Associating the lipid source with vitamin E is possible to obtain an improvement of the antioxidant activity in the buffalo's body, as well as to obtain an improved lipid profile and with good oxidative stability in buffalo milk.