Giovani Fiorentini

Effect of lipid sources with different fatty acid profiles on the intake, performance, and methane emissions of feedlot Nellore steers

The present study was conducted to evaluate the effect of lipids with different fatty acid profiles on the intake, performance, and enteric CH4 emission of Nellore steers. A total of 45 Nellore animals with an average initial BW of 419 ± 11 kg (at 15 ± 2 mo) were distributed in a completely randomized design consisting of 5 treatments and 9 replicates. The roughage feed was maize silage (600 g/kg on a DM basis) plus concentrate (400 g/kg on a DM basis). The dietary treatments were as follows: without additional fat (WF), palm oil (PO), linseed oil (LO), protected fat (PF; Lactoplus), and whole soybeans (WS). The lipid source significantly affected (P < 0.05) nutrient intake. The greatest intakes of DM, OM, and CP were observed in the animals that were fed the WF or PF diets, and the lowest intakes were observed in the animals that were fed the PO diet. Intake of NDF decreased (P < 0.05) with the addition of PO. Enteric methane emission (g/kg DMI) was reduced by an average of 30% when the animals were fed diets containing WS, LO, and PO (P < 0.05), and these diets caused a larger reduction in the energy loss in the form of methane compared to those without added fat and with added PF (3.3 vs. 4.7%). The different fatty acid profiles did not affect the backfat thickness or the loin eye area of the animals (P > 0.05). However, animals fed PO displayed lower daily weight gain (0.36 kg/d), feed efficiency (0.08 kg ADG/kg DM), HCW (245 kg), and hot yield percentage (52.6%) compared to animals that were fed the other diets. Therefore, PO compared to the other lipid sources used in this study reduces intake, performance, feed efficiency, and carcass yield. Therefore, PO is not suggested for feedlot-finished animals.

Qualitative characteristics of meat from confined crossbred heifers fed with lipid sources

Lipids have been used in ruminant feed to replace high amounts of grain for increasing the diet energy density, performance and meat quality. This study evaluated the qualitative characteristics of meat from feedlot heifers fed with sources of lipid supplements. Twenty-one crossbred heifers (1/4Nelore × 1/4Santa Gertrudis × 1/2Braunvieh) were used. Each heifer received 60 % forage with a base of corn silage and 40 % concentrate, resulting in 5.8 % lipid content in the total diet. The following sources of lipids were used: soybeans, protected fat and soybean oil. There were no differences on physical characteristics of meat samples from heifers fed with the lipid sources. Soybeans increased the concentration of linoleic acid, content of polyunsaturated fatty acid and activity of the Δ9-desaturase C16 enzyme in the Longissimus muscle. The use of soybean oil in the diet increased the oleic acid, monounsaturated fatty acid, total cis- and trans-fatty acids (C18:0) and the activity of the Δ9-desaturase C16 enzyme in the subcutaneous fat. Diets with soybean grain had greater deposition of linoleic and linolenic acids than diets with fat protected and greater presence of these essential fatty acids are associated to a better composition and meat quality.

Rumen fermentation and rumen microbes in Nellore steers receiving diets with different lipid contents

The objective of the present study was to evaluate the effects of dietary lipid content (20, 40 and 60 g/kg dry matter) on intake, total and ruminal apparent digestibility of dry matter (DM), nutrient digestibility, rumen fermentation parameters, microbial synthesis efficiency and rumen microbial content of beef cattle. Nine cannulated steers at 6 months of age with initial body weight of 232±35 kg were used in a triplicate 3 × 3 Latin square design. The results indicated that the total intake and digestibility of DM, organic matter (OM), gross energy (GE), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were not affected by the lipid content of the diet. However, the lowest lipid content diet reduced the total digestibility of crude protein (CP) and total carbohydrate linearly compared with the highest lipid diet. In contrast, when steers were fed a diet containing 20 g lipids/kg of DM, the concentration of ammonia in the rumen decreased quadratically relative to the other diets. Ruminal pH was not affected by the interaction of treatment and sampling time; however, the rumen pH decreased quadratically in animals that received the highest dietary lipid content (60 g/kg) compared with animals that received 20 and 40 g lipids/kg of DM. The rumen concentrations of volatile fatty acids, propionate, and butyrate and the acetate/propionate ratio were affected by the dietary lipid content. However, the microbial population, microbial N flow, and efficiency of synthesis were not affected by dietary lipid content. Overall, an increase in the lipid content of the diet of Nellore steers resulted in similar digestive profiles and fermentation conditions.

Lipid Sources with Different Fatty Acid Profile Alters the Fatty Acid Profile and Quality of Beef from Confined Nellore Steers.

The present study was conducted to determine the effects of lipid sources with different fatty acids profile on meat fatty acids profile and beef quality traits of Nellore. A total of 45 Nellore animals with an average initial body weight of 419±11 kg (at 15±2 mo) were distributed in a completely randomized design consisting of 5 treatments and 9 replicates. The roughage feed was maize silage (600 g/kg on a dry matter [DM] basis) plus concentrate (400 g/kg on a DM basis). The dietary treatments were as follows: without fat (WF), palm oil (PO), linseed oil (LO), protected fat (PF), and soybean grains (SG). No effects of lipid sources were observed (p>0.05) on beef color, pH, water-holding capacity, and sarcomere length. Beef from cattle fed PO had greater shear-force values (p<0.05) compared to beef from cattle fed WF. Deposition of main unsaturated fatty acids (oleic, linoleic, and linolenic) was greater in treatments WF, SG, and LO, respectively, while the values of conjugated linoleic acid (CLA) were greater when animals were fed LO. The inclusion of LO in the diet enhances the concentration of CLA in longissimus muscle and subcutaneous fat besides improving the atherogenicity index and elongase activity. As such, LO can be used with the aim to improve the quality of beef from confined Nellore cattle. Conversely, the use of PO is not recommended since it may increase the concentration of undesirable unsaturated fatty acids in muscle and subcutaneous fat, shear-force and the atherogenicity index.

Inovações e desafios na avaliação de alimentos na nutrição de ruminantes

The food evaluation is one of the main points to be observed in the animal nutrition sector, which concerns the use of methods to describe animal feed as well its ability to support different types and levels of animal performance. Currently, researches have tried finding relationship between the nutrient content of foods and their digestive and metabolic exploitation. The animal nutrition is a science rather dynamic, always making use of new technologies and strategies to improve the utilization of food, always searching new methods as new answers to questions are necessary. Thus, the establishment of appropriate methodologies to obtaining the answers is essential to achieve success in search. This way this review will address and discuss some of the main techniques used in feed evaluation applied to ruminant nutrition

Feeding increasing concentrate to Tifton 85 hay ratios modulated rumen fermentation and microbiota in Nellore feedlot steers

The use of diets with increasing proportions of concentrate to fibre can ensure appropriate energy levels and result in greater efficiency in Nellore feedlot steers. It was hypothesized that higher proportions of concentrate in the diet of these Nellore steers may affect ruminal fermentation and microbiota as a consequence of ruminal pH reduction. The present study was conducted to evaluate the effect of diets with four different roughage (hay Tifton 85) : concentrate ratios on intake, digestibility, rumen fermentation and rumen microbiota of Nellore feedlot steers. Higher proportions of concentrate in the diet did not affect intake and digestibility of dry and organic matter. The concentration of N-NH₃, total rumen volatile fatty acid, acetic (C2), butyric (C4), isobutyric, valeric and isovaleric acids, and microbial nitrogen did not differ among diets. However, increasing proportions of concentrate in the diet resulted in a linear reduction in average rumen pH and increased propionic acid (C3) concentration, resulting in lower relative C2 : C3. Bacterial population of Fibrobacter succinogenes, Ruminococus flavefaciens and Ruminococcus albus decreased in the rumen. However, bacteria that are consumers of lactic acid (Selenomonas ruminantium and Megasphaera elsdenii) and producers of lactic acid (Lactobacillus sp. and Streptococcus bovis) increased when animals were fed with high-concentrate diets. The total number of protozoa was similar for the different roughage : concentrate ratios. Protozoan counts were only influenced by diet for the genus Dasytricha. The findings point to diets with increasing concentrate to Tifton 85 hay ratios as inhibiting the growth of some cellulolytic bacteria and reducing fibre digestibility, and indicate Tifton 85 hay as a possible modulated rumen fermentation in the Nellore steer feedlot.

Source and frequency of dry season lipid supplementation of grazing, finishing cattle

The objective of this study was to evaluate the effects of sources of soybean oil [ground soybean (GS), soybean oil (SO) and calcium salts of soybean oil (CS)] on DM intake (DMI), ingestive behaviour and average daily gain (ADG) of heifers grazing marandu palisadegrass (Brachiaria brizantha cv. Marandu) supplemented in two frequencies [daily and 3 days a week (Monday, Wednesday and Friday – MWF)]. The experiment was conducted from July until November of 2007. Forty-two crossbred heifers (1/4 Nellore × 1/4 Santa Gertrudis × 1/2 Braunvieh), 17-months old and 297.1 kg ± 30.5 BW ± s.e.m., were used. Supplements were offered at 0.75% BW.day. Treatments were allocated in a completely randomised design and distributed in a factorial arrangement (3 × 2 – SO from three different sources and two supplementation frequencies). Total DMI was greater in August and October (2.2 kg DM/kg BW) than in November (1.5 kg DM/kg BW). There was an effect of SO source on total DM, herbage and nutrients intake, but no effects of supplementation frequency. The animals supplemented with SO had greater DMI (P < 0.05) than the ones fed GS and CS. Average daily gain (0.580 g) was not affected by supplement sources or feeding frequency. Therefore, GS and CS are more efficient supplements. Supplementation frequency altered grazing time differently according to source. The MWF treatment resulted in a decreased grazing time when GS and SO were fed. However, in days when supplements were not offered, grazing time was increased for GS and CS. It was concluded that a decreased frequency of supplementation may be implemented without effect on weight gain and will reduce labour and machinery costs.

Effects of supplementation frequency on the ruminal fermentation and enteric methane production of beef cattle grazing in tropical pastures

The objective of this study was to evaluate the characteristics of ruminal fermentation and enteric methane production in beef cattle subjected to different supplementation frequencies while grazing on Brachiaria brizanthacv. Marandu pastures. Nine cattle (325±65.7 kg BW) fitted with ruminal and duodenal cannulas were used in the ruminal fermentation study, and 12 cattle (399±32.6 kg BW) were used in the enteric methane production study. The treatments included supplementation once daily, supplementation once daily except Saturdays and Sundays, or supplementation on alternate days. The supplementation was equivalent to 10 g kg−1 BW day−1 for all treatments. The design employed was completely randomized with three treatments and three replications. When all supplements were provided (day 1), no effects of supplementation frequency were observed on ruminal pH; concentration of NH3-N; concentration of acetic, propionic, or butyric acids; or total volatile fatty acids (VFA), but there were month effects. During the day on which only daily supplements were provided (day 2), significant differences were observed only on the molar concentration of acetic acid and total VFA; and month effects were noted on all variables. No significant differences were observed in ruminal fluid volume, dilution rate, N intake, bacterial N synthesis and enteric methane production among the studied supplementation frequencies. Differences were observed in the enteric methane production in the different months, with 85 g kg−1 of gross energy intake observed in September and 123 g kg−1 of gross energy intake observed in November. Lower supplementation frequency is a good option to lower labor costs with little or no consequences on ruminal fermentation characteristics and enteric methane production.

Parameters of fermentation and rumen microbiota of Nellore steers fed with different proportions of concentrate in fresh sugarcane containing diets

ABSTRACT The objective of this study was to evaluate the effect of a fresh sugarcane-based diet and different roughage-to-concentrate ratios (70:30, 60:40, 40:60 and 20:80) on the rumen microbiota associated with rumen fermentation parameters and the intake and apparent digestibility of nutrients in Nellore steers. Eight rumen-cannulated Nellore steers (331 ± 8 kg BW) were distributed in a double 4 × 4 Latin square design balanced for the control of the residual effect. The ruminal pH decreased (p < 0.01) and the concentrations of N–NH3, isovaleric and valeric acids increased linearly (p < 0.05) with an increase dietary concentrate level. Furthermore, an increased concentrate proportion reduced the population of Fibrobacter succinogenes and Ruminococus flavefaciens (p < 0.01) and increased the population of Selenomonas ruminantium and Megasphaera elsdenii (p < 0.01). The protozoa count revealed a predominance of the genus Entodinium. The synthesis of microbial N [g/d] and the efficiency of microbial synthesis [g of microbial N/kg of organic matter apparently digested in the rumen] increased as the proportion of concentrate was increased (p < 0.05). Therefore, it can be concluded that an increasing proportion of concentrate in sugarcane-containing diets enhances the synthesis of microbial protein and does not alter the fibre digestibility, although the population of fibre fermenting bacteria was reduced.

Effects of different sources of forage in high-concentrate diets on fermentation parameters, ruminal biohydrogenation and microbiota in Nellore feedlot steers

Modifying the extent of fatty acid (FA) biohydrogenation (BH) in the rumen through diet formulation is an effective strategy for changing the content of unsaturated FAs (USFAs) in meat. The present study investigated the effects of different sources of forage in high-concentrate diets on intake, digestibility, rumen fermentation, ruminal BH, duodenal flow of FAs and rumen microbiota in Nellore steers. Intake of neutral detergent fibre (NDF) was higher in animals fed with maize silage (MS) than in those fed with sugar cane (SC) and sugar cane bagasse (SB). Higher digestibility of dry matter and NDF was found in animals fed with MS than in those fed with the other diets. In addition, higher crude protein digestibility was observed in animals fed with sugar cane bagasse than in those fed with SC. Non-fibre carbohydrate (NFC) digestibility was higher in animals fed with sugar cane than in those fed with the other diets. Intake of total and individual FAs such as C18 : 1 cis -9, C18 : 2, and C18 : 3 was similar between animals fed with MS and SB, but decreased in animals fed with SC. Diets containing MS and SB showed higher total digestibility of saturated FAs (SFAs) and USFAs, respectively and total FAs and ruminal BH of C18 : 1 and USFA. Intestinal digestibility of overall FAs did not differ among treatments, except for C18 : 3, which increased in animals fed with SC and SB. The profile of FAs in duodenal digesta and faecal outputs did not differ among treatments. However, the flow of NDF was higher in animals fed with SC than in those fed with MS and SB. Animals fed with SB showed higher values of pH than those fed with MS and SC. Animals fed with SC showed lower values of ammonia-nitrogen. Protozoan counts were only influenced by diet for species that belonged to the genera Dasytricha and Isotricha . Populations of fibrolytic bacteria ( Ruminococus flavefaciens, Ruminococus albus and Fibrobacter succinogenes ) were similar among diets. Populations of Selenomonas ruminantium increased 2·5 and 5 times in animals fed with MS when compared with those fed with SC and SB, respectively. The use of MS increased intake and digestibility of NDF, and the use of SC decreased ruminal BH of total USFA without changing the flow of FAs to the duodenum. Thus, different sources of forage in high-concentrate diets do not modify the duodenal flow of USFA or fibrolytic bacteria. This must be taken into account when formulating diets to modulate ruminal upsets without altering intake.