RESUMO

Bioactive fatty acids present in goat milk have the ability to reduce the risks of coronary heart disease in humans, and condensed tannins (CT) can modulate the polyunsaturated fatty acids (PUFA) biohydrogenation process in the rumen and consequently increase the levels of these fatty acids. Thus, the objective was to evaluate the inclusion of CT in the diet for Canindé, Repartida, and Saanen goats to increase the level of bioactive fatty acids in milk. Twenty-two lactating does of three genetic groups, six Canindé, eight Repartida, and eight Saanen, were randomly assigned in a 3 × 2 factorial arrangement of three genetic groups and two diets (control and with 50 g CT/kg DM). The inclusion of CT in the diet did not change (P > 0.05) nutrient intake and performance. However, the inclusion of CT promoted an increase (P < 0.05) in C14:1; cis-9; C18:2n6; C18:3n6; C18:3n3; PUFA; and long-chain fatty acids and reduction (P < 0.05) of C11; C12; C14; ω6/ω3; and atherogenicity index in milk fat. Thus, it is recommended to include CT in the diet for Canindé, Repartida, and Saanen goats to increase the level of bioactive fatty acids in milk. The inclusion of the tannins of Acacia mearnsii promoted an increase in C14:1; cis-9; C18:2n6; C18:3n6; C18:3n3; polyunsaturated fatty acid; and long-chain fatty acids and reduction of C11; C12; C14; ω6/ω3; and atherogenicity index in milk fat.

Assuntos

RESUMO

Conjugated linoleic acid (CLA), has been shown to have protective effects against various diseases, such as obesity, arteriosclerosis, diabetes, chronic inflammatory diseases, and cancer. This fatty acid in ruminants results from two processes, biohydrogenation, which takes place in the rumen, and de novo synthesis, carried out in the mammary gland, and it has linoleic and α-linolenic acids as its precursors. The amounts of precursors in the diets of animals are related to the amounts of CLA in milk. In the literature review, it was found that the milk of cows fed fresh forage has a higher amount of CLA because they have a higher amount of linoleic acid and α-linolenic acid compared to other foods used in the diets of cows. The amount of CLA precursors in pastures can be increased through agronomic practices, such as nitrogen fertilization, and regrowth age. It is also a technique used to increase the amount of CLA in milk to obtain a greater benefit regarding its nutritional value.

RESUMO

Our current understanding of the effect of medium-chain FA (MCFA) rich vegetable oils on ruminant nutrition is limited. We assessed the effects of babassu or buriti oil addition to the diet of lambs on intake, nutrient digestibility, FA profile of abomasal digesta content and biohydrogenation (BH) patterns in digestion. The experimental diets were defined by the addition of babassu oil or buriti oil to the diet, as follows: (1) non-supplemented diet (CON); (2) 40 g/kg of babassu oil (BAO, rich in C12:0); and (3) 40 g/kg of buriti oil (BUO, rich in c9 18:1), on a dry matter (DM) basis. During the last five days of the feedlot, samples of orts and feces were individually collected to determine the nutrient and FA digestibility. At the end of the experiment, animals were slaughtered, and the abomasal digesta was collected, freeze-dried and used for FA determinations conducted by gas chromatography. The BAO diet decreased the DM (p = 0.014) and nutrient intake. The lambs fed BUO had the greatest FA intake, followed by the BAO and CON diets. However, BAO increased total FA digestibility, compared with CON, but did not differ from BUO. The BAO diet extensively changed the FA composition of abomasal digesta when compared with both the CON and BUO diets. The BAO diet also increased C12:0 and C14:0, the sum of PUFA and the BH intermediates FA, including the t-10-18:1 but decreased the C18:0 in abomasal digesta. The BUO addition had the greatest total-FA and C18:0 and the lowest biohydrogenation intermediate content in abomasal digesta. The BH was less complete with the BAO diet and a large increase in t10-18:1 and of t10-/t11-18:1 ratio was observed, which indicates the occurrence of t10 possibly shifted rumen BH pathways, probably as a response to bacterial membrane stress induced by the greater C12:0 concentration in the rumen.

RESUMO

Conjugated linoleic acid (CLA) has been the subject of numerous studies in recent decades because of its associated health benefits. CLA is an intermediate product of the biohydrogenation pathway of linoleic acid (LA) in bacteria. Several bacterial species capable of efficiently converting LA into CLA have been widely reported in the literature, among them Lactobacillus delbrueckii subsp. bulgaricus LBP UFSC 2230. Over the last few years, a multicomponent enzymatic system consisting of three enzymes involved in the biohydrogenation process of LA has been proposed. Sequencing the genome of L. delbrueckii subsp. bulgaricus LBP UFSC 2230 revealed only one gene capable of encoding an oleate hydratase (OleH), unlike the presence of multiple genes typically found in similar strains. This study investigated the biological effect of the OleH enzyme of L. delbrueckii subsp. bulgaricus LBP UFSC 2230 on the hydration of LA and dehydration of ricinoleic acid (RA) and its possible role in the production of CLA. The OleH was cloned, expressed, purified, and characterized. Fatty acid measurements were made by an internal standard method using a gas chromatography-coupled flame ionization detector (GC-FID) system. It was found that the enzyme is a hydratase/dehydratase, leading to a reversible transformation between LA and RA. In addition, the results showed that L. delbrueckii subsp. bulgaricus LBP UFSC 2230 OleH protein plays a role in stress tolerance in Escherichia coli. In conclusion, the OleH of L. delbrueckii subsp. bulgaricus LBP UFSC 2230 catalyzes the initial stage of saturation metabolism of LA, although it has not converted the substrates directly into CLA. IMPORTANCE This study provides insight into the enzymatic mechanism of CLA synthesis in L. delbrueckii subsp. bulgaricus and broadens our understanding of the bioconversion of LA and RA by OleH. The impact of OleH on the production of the c9, t11 CLA isomer and stress tolerance by E. coli has been assisted. The results provide an understanding of the factors which influence OleH activity. L. delbrueckii subsp. bulgaricus LBP UFSC 2230 OleH presented two putative fatty acid-binding sites. Recombinant OleH catalyzed both LA hydration and RA dehydration. OleH was shown to play a role in bacterial growth performance in the presence of LA.

Assuntos

RESUMO

Sub-acute ruminal acidosis (SARA) is sometimes observed along with reduced milk fat synthesis. Inconsistent responses may be explained by dietary fat levels. Twelve ruminally cannulated cows were used in a Latin square design investigating the timing of metabolic and milk fat changes during Induction and Recovery from SARA by altering starch levels in low-fat diets. Treatments were (1) SARA Induction, (2) Recovery and (3) Control. Sub-acute ruminal acidosis was induced by feeding a diet containing 29.4% starch, 24.0% NDF and 2.8% fatty acids (FAs), whereas the Recovery and Control diets contained 19.9% starch, 31.0% NDF and 2.6% FA. Relative to Control, DM intake (DMI) and milk yield were higher in SARA from days 14 to 21 and from days 10 to 21, respectively (P < 0.05). Milk fat content was reduced from days 3 to 14 in SARA (P < 0.05) compared with Control, while greater protein and lactose contents were observed from days 14 to 21 and 3 to 21, respectively (P < 0.05). Milk fat yield was reduced by SARA on day 3 (P < 0.05), whereas both protein and lactose yields were higher on days 14 and 21 (P < 0.05). The ruminal acetate-to-propionate ratio was lower, and the concentrations of propionate and lactate were higher in the SARA treatment compared with Control on day 21 (P < 0.05). Plasma insulin increased during SARA, whereas plasma non-esterified fatty acids and milk ß-hydroxybutyrate decreased (P < 0.05). Similarly to fat yield, the yield of milk preformed FA (>16C) was lower on day 3 (P < 0.05) and tended to be lower on day 7 in SARA cows (P < 0.10), whereas yield of de novo FA (<16C) was higher on day 21 (P < 0.01) in the SARA group relative to Control. The t10- to t11-18:1 ratio increased during the SARA Induction period (P < 0.05), but the concentration of t10-18:1 remained below 0.5% of milk fat, and t10,c12 conjugated linoleic acid remained below detection levels. Odd-chain FA increased, whereas branched-chain FA was reduced during SARA Induction from days 3 to 21 (P < 0.05). Sub-acute ruminal acidosis reduced milk fat synthesis transiently. Such reduction was not associated with ruminal biohydrogenation intermediates but rather with a transient reduction in supply of preformed FA. Subsequent rescue of milk fat synthesis may be associated with higher availability of substrates due to increased DMI during SARA.

Assuntos

RESUMO

This study was performed with the main objective of evaluating the effect of the combination of pelleting and monensin on fatty acids (FA) composition, the concentration of total polyphenols and flavonoids, and the oxidative stability of milk in cows fed a concentrate containing soybean seeds. Eight Holstein multiparous cows were distributed in a replicated Latin square design. The four supplement treatments consisted of the combination of two factors (pelleting and monensin) and one concentrate as follows: (1) unpelleted concentrate with no monensin (CO); (2) pelleted concentrate with no monensin (PE); (3) unpelleted concentrate with 96 mg of monensin/kg of dry matter, DM (MO); and (4) pelleted concentrate with 96 mg of monensin/kg of DM (PM). There was no interaction between pelleting and monensin for milk production and concentration of milk protein, lactose, total polyphenols, flavonoids, conjugated dienes (CD), and reducing power. Fat and total solids concentration in milk were decreased when cows were fed pelleted (PE and PM) concentrates. Feeding cows with PE and PM concentrates increased the CD concentration in milk. Regarding milk FA concentration, there was no difference among treatments for total saturated, monounsaturated, and polyunsaturated FA. The most prominent result was that pelleting increased the milk concentration of omega-3 FA. Altogether, the present study suggests that the pelleting process can improve the milk fat quality by increasing the omega-3 FA, while the combination of pelleting and monensin in the diet of grazing dairy cows fed soybean-based concentrate adds no further improvements to FA profiles and oxidative stability of milk.

Assuntos

RESUMO

The objective of this study was to evaluate the effects of algae and cottonseed meal (CSM) supplementation on the fatty acid (FA) profile in the rumen fluid (RF) of steers fed a low-quality forage. Five Bos indicus crossbred steers, 187±7.5 kg liveweight (LW; mean±SD), were fed a low crude protein speargrass (Heteropogon contortus) hay as the basal diet alone or supplemented with either Spirulina platensis, Chlorella pyrenoidosa , Dunaliella salina , or CSM in Latin square design. The proportion of individual FA in the RF of steers varied in response to supplement, and these were most likely due to differences in the FA profile in supplements. Steers supplemented with Chlorella pyrenoidosa and CSM had a higher concentration of linoleic acid (C18:2n-6) in RF than unsupplemented steers or steers offered the other supplements, but there was no difference in the concentration in RF in steers supplemented with Chlorella pyrenoidosa and CSM. The concentration of linolenic acid (C18:3n-3) was higher in the RF of unsupplemented steers compared with supplemented steers. Steers receiving Chlorella pyrenoidosa supplementation showed an increase in total unsaturated FA in the RF compared with other supplemented and unsupplemented steers, which if transferred to meat, could have health related benefits to consumers. None of the supplements led to the formation of isomers known to inhibit fat synthesis.(AU)

Assuntos

RESUMO

This study describes the chemoselective hydrogenation reaction of halogenated 2'-hydroxychalcones by the marine-derived fungus Penicillium raistrickii CBMAI 931. Initially, 2'-hydroxychalcone was utilized as a model for the selection of the appropriate conditions to perform the biotransformation reactions. The best results were obtained using mycelia and filtered culture broth, and this condition was chosen for the biotransformation reaction of 2'-hydroxychalcones substituted with methoxy and halogen groups. Experiments performed with 2'-hydroxychalcones dissolved in 600 µL-DMSO were more effective than those performed using 300 µL-DMSO, once solubility of the compounds influenced conversion rate in the liquid medium. The halogenated 2'-hydroxy-dihydrochalcones were obtained in good conversions (78-99%) and moderate isolated yields (31-65%). All biotransformation reactions using the marine-derived fungus P. raistrickii CBMAI 931 showed regioselective and chemoselective control for the formation of 2'-hydroxy-dihydrochalcones.

Assuntos

RESUMO

The aim of the study was to evaluate the effect of different forage sources in diets for feedlot dairy cows and their implications on production, composition, fatty acid profile, and milk cholesterol content. Nine Holstein × Zebu crossbred cows were distributed in three 3 × 3 Latin squares, in three periods of 21 days each, and three diets: elephant grass silage + concentrate, briquette from Brachiaria + concentrate, and sugarcane + concentrate. Elephant grass silage resulted in lower milk production and milk protein content. Cows fed elephant grass silage had lower concentrations of the saturated fatty acids C10:0, C11:0, C12:0, and C15:0 in the milk and higher of the unsaturated fatty acids C15:1, C16:1, C18:1n-9t, C18:1n-9c, C18:3n-6, CLAc9t11, and CLAt10c12 in relation to the other diets. Data were analyzed using the GLM procedure of the Statistical Analysis System (SAS) and the means were compared by the Tukey's test (P = 0.05). It is recommended to use the briquette from Brachiaria as a forage source for lactating cows, since it led to higher milk yield. On the other hand, the use of elephant grass silage as a forage source is recommended if the farmer is paid for milk with higher concentration of monounsaturated and polyunsaturated (CLA) fatty acids, which exerts beneficial effects on human health.

Assuntos

RESUMO

O uso de pastagens consorciadas de gramíneas e leguminosas promove uma série de benefícios a todo o sistema de produção. Contudo, seu emprego ainda é modesto e seus benefícios são postos a prova constantemente. Diante disto, o objetivo desta revisão é fomentar a discussão sobre o uso de pastagens consorciadas e sua relação com a produção, composição e características nutricionais do leite, além da sua relação com a sustentabilidade do sistema. De maneira geral, participações entre 20 e 30% de leguminosas no dossel forrageiro são suficientes para promover incrementos de produção de leite em comparação a sistemas exclusivamente de gramíneas. Este aumento está relacionado ao menor percentual de fibras da pastagem, o que permite maior ingestão e digestibilidade da matéria seca. Salienta-se ainda que estes efeitos não sejam lineares e que os percentuais citados devem nortear a condução dos sistemas. Quanto ao perfil nutricional do leite, os níveis de ácidos graxos insaturados (AGI) são maiores nos animais à pasto em relação aos confinados. No entanto, são menos comuns pesquisas que comparem o perfil de ácidos graxos do leite em função de pastagens mistas ou estremes, de maneira geral, leguminosas como os trevos possuem compostos secundários que podem facilitar a passagem de AGI pelo rúmen sem sofrerem ação da biohidrogenação. Além destes efeitos, o uso de pastagens consorciadas permite a redução do uso de fertilizantes nitrogenados, aspecto importante do ponto de vista ambiental. O uso de sistemas alimentares a base de pastagem consorciada de gramíneas e leguminosas pode significar melhorias na qualidade nutricional do leite, como o aumento do percentual de AGI, que são veementemente associados a uma alimentação mais saudável.

The use of intercropped grasses and legumes promotes a number of benefits to the entire production system. However, their employment is still modest and their benefits are constantly put to the test. In view of this, the purpose of this review is to promote the discussion about the use of intercropped pastures and their relationship with milk production, composition and nutritional characteristics, as well as their relationship with the sustainability of the system. In general, participation of 20 to 30% of legumes in the forage canopy is sufficient to promote increases in milk production compared to exclusively grass systems. This increase is related to the lower percentage of grazing fibers, which allows higher intake and dry matter digestibility. It should also be noted that these effects are not linear and that the percentages mentioned should guide the systems. As for the nutritional profile of milk, the levels of unsaturated fatty acids (AGI) are higher in the pasture than in the confined ones. However, research comparing the fatty acid profile of milk as a function of mixed or single pastures is generally less common, as legumes like cloves have secondary compounds that may facilitate the passage of AGI through the rumen without undergoing biohydrogenation. In addition, the use of intercropping pastures allows a reduction in the use of nitrogen fertilizers, an important aspect from the environmental point of view. The use of food systems based on intercropping grasses and legumes can mean improvements in the nutritional quality of milk, such as the increase in the percentage of AGI, which are strongly associated with a healthier diet.

Assuntos