Metabolism In Lambs Research Articles

Influence of supplementing diet with microalgae (Schizochytrium limacinum)on growth and metabolism in lambs during the summer

The current experiment was conducted to examine the impact of a supplement of microalgae ( Schizochytrium limacinum ) on the performance, rumen fermentation, and blood metabolites in lambs during summer. Forty lambs were used in a 49-day experiment. The lambs were group-fed either a basal diet (alfalfa hay and concentrate, n = 20) or the basal diet along with 5 g/day microalgae (n = 20). Feed intakes were recorded daily and body weight (BW) was measured weekly. Overall, microalgae feeding increased (P 0.05). Microalgae feeding decreased rumen pH (P < 0.05) and tended to reduce proportion of acetate (P < 0.1), while it increased total rumen volatile fatty acid concentration (8.6%; P < 0.01) and proportions of propionate (13.9%, P < 0.01) and valerate (P < 0.01; 26.5%) compared with the control animals. Microalgae feeding increased (P < 0.05) blood glucose (98.47 vs. 84.97 mg/dL) and insulin (64.14 vs. 29.26 ng/mL), whereas it lowered total cholesterol concentrations in blood (62 vs. 58 mg/dL, P < 0.1) compared with the control animals. The results of this study indicate that microalgae supplement influences productivity and enhances dietary energy utilization in lambs during the summer.

1345 Monensin and levels of narasin on rumen metabolism in lambs during adaptation to high-concentrate diets

1345 Monensin and levels of narasin on rumen metabolism in lambs during adaptation to high-concentrate diets

1347 Monensin and levels of narasin on rumen metabolism in lambs fed high-concentrate diets

1347 Monensin and levels of narasin on rumen metabolism in lambs fed high-concentrate diets

Poor maternal nutrition during gestation alters the expression of genes involved in muscle development and metabolism in lambs.

Poor maternal nutrition during gestation can result in reduced muscle mass and increased adiposity of the muscle tissue in the offspring. This can have long-lasting consequences on offspring health and productivity. However, the mechanisms by which poor maternal nutrition affects postnatal muscle development are poorly understood. We hypothesized that poor maternal nutrition during gestation would alter expression of key pathways and genes involved in growth, development, and maintenance of the muscle of lambs. For this study, beginning at d 31 ± 1.3 of gestation, ewes were fed 100 (control), 60 (restricted), or 140% (overfed) of the NRC requirements. Within 24 h of birth, lambs were necropsied and semitendinosus muscle tissue was collected for gene expression analysis. Using RNA sequencing (RNA-seq) across dietary treatment groups, 35 and 10 differentially expressed genes were identified using the and reference annotations, respectively. Maternal overfeeding caused changes in the expression of genes involved in regulating muscle protein synthesis and growth as well as metabolism. Alternately, maternal nutrient restriction affected genes that are involved in muscle cell proliferation and signal transduction. That is, despite a similar phenotype, the genes identified differed between offspring born to restricted- or overfed, ewes indicating that the mechanism for the phenotypic changes in muscle are due to different mechanisms.

Nitrogen metabolism in lambs fed diets containing peach palm meal.

The objective of this study was to evaluate the nitrogen metabolism of lambs fed diets containing peach palm meal substituting maize (0, 10, 40, 60, and 85% DM). Thirty Santa Inês uncastrated lambs with an average initial body weight of 21.6 ± 0.87kg were distributed in a completely randomized design with five diets and six replicates. The nitrogen (N) intake (g/day, %BW) and the fecal N decreased linearly as the peach palm meal was added to the concentrate. The urinary N, however, responded quadratically, with maxima at the level of 29.97 and 40.44% of substitution of maize for peach palm meal when expressed in g/day and %BW, respectively. The substitution of maize for peach palm meal reduced the retention of nitrogen and the microbial protein synthesis in the lambs.

Effects of lamb early starter feeding on the expression of genes involved in volatile fatty acid transport and pH regulation in rumen tissue

The objective of this study was to investigate the effects of early starter feeding on ruminal pH regulation and the expression levels of genes involved in rumen volatile fatty acid (VFA) metabolism in lambs. A total of 78 male Hu lambs with similar born body weights were selected. Six lambs were slaughtered immediately after birth, and the remaining 72 were equally divided into a group fed by starter diet 1 at day 7 or a group fed by starter diet 1 at day 42. The lambs from both groups were weaned at day 56 and transacted to starter diet 2 at day 59. Six lambs from each group were randomly slaughtered at days 14, 28, 42, 56, 70 and 84, respectively. The results revealed that the ruminal VFA concentration in the early provision group was higher (P<0.05) than that in late provision group, while the rumen pH was not affected (P>0.05) by early or late starter feeding. Treatment-age interactions (P<0.05) and age alone (P<0.05) affected the expressions of NHE2, NHE3, DRA, HMGCL and MCT1. The expression of NHE2, DRA and HMGCL in early provision group were lower (P<0.05) than that in late provision group. However, the expression of MCT1 in early provision group was higher (P<0.05) than that in the late provision group. The findings of this study show that early starter feeding in lambs can increase the ruminal VFA concentration and affect the expression levels of genes involved in VFA transport and pH regulation in the ruminal epithelium.

Nutrient digestibility and ruminal fatty acid metabolism in lambs supplemented with soybean oil partially replaced by fish oil blend

The objective of these experiments was to evaluate the effects of partially replacing soybean oil with small amounts of fish oil blend on the intake and digestibility of nutrients, ruminal SCFA and pH, and duodenal flow of fatty acids. Five ram lambs rumen and proximal duodenum-cannulated (51.7±3.1kg of initial BW; mean±SD) were assigned to a 5×5 Latin square design. The oils were added to a basal diet that contained 900g/kg DM of concentrate (corn, soybean meal, soybean hulls, urea, ammonium chloride, limestone, mineral mix, and Rumensin® 100) and 100g/kg DM of forage (fresh sugarcane bagasse). The treatments were as follows: (1) basal diet without added oil (CONT); (2) 40g/kg DM of soybean oil (0FO); (3) 2.5g/kg DM of fish oil blend+37.5g/kg DM of soybean oil (2.5FO); (4) 5g/kg DM of fish oil blend+35g/kg DM of soybean oil (5.0FO); and (5) 7.5g/kg DM of fish oil blend+32.5g/kg DM of soybean oil (7.5FO). All diets were isonitrogenous (160±3g/kg DM of CP). Intakes of DM, organic matter (OM), non-fiber carbohydrates (NFC), and neutral detergent fiber (NDF) (kg/d) were not affected by the treatments. The apparent digestibility of DM, OM, and NDF were similar for all diets. The soybean oil and fish oil blend supplements decreased CP digestibility. Total fatty acids digestibility and total digestible nutrients (TDN) were higher in the diets with oils in comparison to the control diet. Ruminal concentrations of acetate, butyrate, and total short chain fatty acids (SCFA) were higher for animals fed the control diet. The ruminal pH was lower for animals consuming the control diet in comparison to the diets with oils. The duodenal flow of C18:0 and C18:1 trans-11 was greater for ram lambs that received soybean oil supplements, and the duodenal flow of C18:1 trans-11 and CLA C18:2 cis-9, trans-11 was greater for diets with oils. In addition, C18:1 trans-11 flow to the duodenum increased linearly as fish oil blend was added to the diets. The ruminal biohydrogenarion of C18:2 cis-12; C18:3 cis-9, cis-12, cis-15, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids were similar for all diets. When associated with high amounts of soybean oil, only a small amount of fish oil blend (2.5g/kg DM) was necessary to optimize the ruminal concentration of CLA. In spite of this finding, the addition of 7.5g/kg DM of fish oil blend mixed with 32.5g/kg DM of soybean oil is recommended, because it increased the duodenal flow of C18:1 trans-11 vaccenic acid. Using soybean oil as the only source of additional fat improved the lipid profile of the duodenal contents, but the partial replacement of soybean oil with fish oil blend shown to be a more efficient strategy to raise the profile of fatty in the duodenal content.

Effect of the Ratio of Non-fibrous Carbohydrates to Neutral Detergent Fiber and Protein Structure on Intake, Digestibility, Rumen Fermentation, and Nitrogen Metabolism in Lambs.

This study aimed to investigate the effect of the ratio of non-fibrous carbohydrates to neutral detergent fibre (NFC/NDF) and undegraded dietary protein (UDP) on rumen fermentation and nitrogen metabolism in lambs. Four Dorper×thin-tailed Han crossbred lambs, averaging 62.3±1.9 kg of body weight and 10 mo of age, were randomly assigned to four dietary treatments of combinations of two levels of NFC/NDF (1.0 and 1.7) and two levels of UDP (35% and 50% of crude protein [CP]). Duodenal nutrient flows were measured with dual markers of Yb and Co, and microbial N (MN) synthesis was estimated using 15N. High UDP decreased organic matter (OM) intake (p = 0.002) and CP intake (p = 0.005). Ruminal pH (p<0.001), ammonia nitrogen (NH3-N; p = 0.008), and total volatile fatty acids (p<0.001) were affected by dietary NFC/NDF. The ruminal concentration of NH3-N was also affected by UDP (p<0.001). The duodenal flow of total MN (p = 0.007) was greater for lambs fed the high NFC/NDF diet. The amount of metabolisable N increased with increasing dietary NFC:NDF (p = 0.02) or UDP (p = 0.04). In conclusion, the diets with high NFC/NDF (1.7) and UDP (50% of CP) improved metabolisable N supply to lambs.

Fatty acid metabolism in lambs fed citrus pulp.

In the present study, we have hypothesized that replacing barley with high proportions of dried citrus pulp in a concentrate-based diet for lambs could increase the intake of unsaturated fatty acids and could reduce the rate of the ruminal biohydrogenation of PUFA, with a consequent improvement of the intramuscular fatty acid composition. To test this hypothesis, 26 Comisana lambs were divided into 3 groups and for 56 d were fed a barley-based concentrate diet (CON; 8 lambs) or 2 diets in which barley was replaced with 24% (CIT24; 9 lambs) or 35% (CIT35; 9 lambs) dried citrus pulp. An overall improvement of the fatty acid composition of LM from lambs fed citrus pulp-containing diets was found. The PUFA/SFA ratio was lower (P < 0.05) in the LM from lambs in the CON group compared with both the CIT24 and CIT35 groups. The thrombogenic index was lower (P < 0.05) in meat from lambs fed the CIT35 diet compared with those fed the CON diet. The CIT35 diet increased the proportion of C20:5 n-3 in the LM (P < 0.05), whereas the CIT24 diet enhanced that of C22:6 -3 (P < 0.05) compared with the CON diet. Some of these results might be explained considering that feeding the CIT24 and CIT35 diets increased the intake of total fatty acids (P < 0.05) and of C18:3 n-3 (P < 0.01) compared with feeding the CON treatment. On the other hand, phenolic compounds present in citrus pulp could have inhibited the ruminal biohydrogenation of PUFA. This is supported by the fact that regardless of the level of inclusion in the diet, citrus pulp increased the proportion of rumenic acid (P < 0.001) in LM compared with the CON diet. The plasma from lambs fed both CIT24 and CIT35 diets had a greater percentage of vaccenic acid (VA; < 0.001) compared with that from lambs fed the CON diet, and the CIT35 diet increased the proportion of rumenic acid in plasma compared with the CON treatment (P < 0.05). In the ruminal fluid, stearic acid (SA) tended to decrease, and the sum of CLA tended to increase (P = 0.09) with increasing level of citrus pulp in the diets. Furthermore, the SA/(SA + VA) ratio tended to be lower (P = 0.10) in the ruminal fluid from lambs fed the CIT35 diet compared with that of the CON group. In conclusion, our results support the hypothesis that replacing barley with citrus pulp in the diet of growing lambs improves intramuscular fatty acid composition and underline the need for specific studies to clarify the mechanisms by which feeding citrus pulp affects the fatty acid metabolism in ruminants.

Avaliação metabólica do uso de probiótico ou monensina em cordeiros mantidos em semi-confinamento

The objective of this study was to verify probiotics and monensin effects on metabolic parameters in weaning lambs. In the experiment 1, thirty lambs divided in three groups were fed during 6 weeks. The lambs were enrolled in one of the following treatments: GC1: as a control, GB1: Bacillus cereus var. toyoi (1x106 spores/g) and GS1: Saccharomyces boulardii (1x106 viable cells/g). In the experiment 2, thirty lambs divided in three groups were fed during 8 weeks. The treatments consisted in GC2: as a control, GM2: monensin (500g/t) and GS2: Saccharomyces boulardii (1x106viable cells/g). In both experiments blood samples were collected weekly aiming to measure metabolic parameters as glucose, triacylglycerol (TAG), cholesterol, albumin, urea, aspartate amino transferase (AST), creatinine kinase (CK) and gamma glutamil transferase (GGT). The results from experiment 1 demonstrated that GS1 had greater (P&lt;0.05) concentrations of albumin and urea during the adaptation period. In the postadaption period the GC1 demonstrated increased (P&lt;0.05) concentrations of cholesterol, albumin and AST activity, in contrast, reduced (P&lt;0.05) concentrations of glucose, urea and CK in comparison to GS1. However, during experiment two throughout the adaptation period the GS2 had greater (P&lt;0.05) concentrations for albumin and urea. The GM2 had greater (P&lt;0.05) concentrations for TAG and lower (P&lt;0.05) for glucose and CK activity. During the post-adaption period the GS2 showed the lowest (P&lt;0.05) concentrations for cholesterol and GGT activity, GC2 had greater (P&lt;0.05) levels of albumin and AST activity as well as lower concentrations for urea. The GM2 had greater levels for GGT activity and lower levels for CK activity. Therefore, it is concluded that protein metabolism in lambs has better performance when Saccharomyces boulardii is added in the ration during the adaptation period. However, during post-adaptation period, monensin is more beneficial for the protein metabolism, once it does not interfere in the muscles catabolism.

Source of Copper May Have Regressive Effects on Serum Cholesterol and Urea Nitrogen Among Male Fattening Lambs

An experiment was conducted to determine the effect of dietary copper (Cu) on mineral profile, hematological parameters, and lipid metabolism in lambs. Eighteen Zandi male lambs (approximately 3 months of age; 17.53±1.6 kg of body weight) were housed in individual pens and were assigned randomly to one of three treatments. Treatments consisted of (1) control (no supplemental Cu), (2) 10 mg Cu/kg dry matter (DM) from copper sulfate (CuS), and (3) 10 mg Cu/kg DM from Cu proteinate (CuP). The Cu concentration was 8.2 mg/kg DM in the basal diet. Blood was sampled from the jugular vein at the beginning of the study (enrollment, before feeding Cu supplement) and at days 25, 50, and 70 of experiment. The amounts of total serum glucose, urea nitrogen, calcium, phosphorus, iron, copper, zinc, and lipids and hematological parameters were measured. Average daily gain and feed efficiency were improved (P<0.05) with Cu supplementation and were better for the lambs fed diet supplemented with CuP. The concentrations of serum Ca, P, and Zn were not affected by source of Cu in the diet. However, Fe concentration was lower (P<0.01) in the Cu-supplemented groups. Experimental treatment had no significant effects on the hematological parameters. The serum glucose concentration was not affected by treatments. However, the urea nitrogen concentrations were significantly affected (P<0.05) by added Cu and was lower for CuP group as compared to the lambs in the CuS and control groups. Addition of Cu had no influence (P>0.05) on the serum triglyceride concentration, but lambs fed with CuP supplement had lower (P<0.05) serum cholesterol than the CuS and control animals. These results indicated that CuP supplemented at 10 mg/kg DM improved gain and enhanced the efficiency of nitrogen in male lambs.

Consumo, digestibilidade e balanço de nitrogênio de cordeiros alimentados com alto teor de amido ou fibra solúvel em detergente neutro associados ao óleo de girassol

The aim of this study was to evaluate the effect of different carbohydrate sources associated with sunflower oil on intake, digestibility of nutrients and nitrogen balance in diets of lambs. Twenty lambs were used, assigned in a completely randomized design with a 2 x 2 factorial arrangement of treatments with two sources of neutral detergent soluble carbohydrate, starch and neutral detergent soluble fiber, with and without the inclusion of 4.2% sunflower oil. The dry matter intake was not affected by carbohydrate sources and the inclusion of oil. Diets with a high percentage of starch provided higher digestibility of dry matter, starch and ether extract. The different sources of carbohydrates had no interference on digestibility of organic matter, crude protein, neutral detergent soluble fiber, nonfiber carbohydrates, neutral detergent fiber, hemicellulose and acid detergent fiber. The addition of oil in the diets increased the digestibility of ether extract. The combination of 4.2% oil in the diet high in soluble neutral detergent fiber had no influence on the nutrient digestibility, otherwise, the addition of oil at high starch diet caused a significant reduction in the digestibility of organic matter, neutral detergent fiber, hemicellulose and nonfiber carbohydrates. The quantities of nitrogen intake, absorbed and retained, did not differ as sources of carbohydrates and oil inclusion in the diet. The association of 4.2 % sunflower oil to the different sources of carbohydrates in the diet does not affect consumption and nitrogen metabolism in lambs. The addition of 4.2 % oil in the diet with high starch (28% of DM diet) promotes reduction in digestibility of organic matter, of fibrous and nonfibrous carbohydrate in the diet.

Effects of slow-release urea and molasses on ruminal metabolism of lambs fed with low-quality tropical forage

The effects of two sources of slow-release urea (SRU) with a source of soluble carbohydrates on ruminal fermentation in lambs fed with a low-quality forage hay were evaluated. Optigen is a commercial source of slow-release urea, whereas Surelease is an ethyl cellulose-coated urea prepared in the Laboratorio de Farmacotecnia at the Metropolitan Autonomous University. Five Pelibuey lambs cannulated in the rumen and duodenum (24.8±0.4kg BW) were used in a Latin Square design. Lambs were fed a basal diet that consisted of Brachiaria brizantha hay and concentrate (ratio 67:33) with the following treatments: (1) feed-grade urea; (2) Surelease-coated urea (SRU-S); (3) SRU-S+molasses; (4) SRU Optigen (OPT); and (5) OPT+molasses. All sources of urea were dosed daily intra-ruminally (0.6g/kg/BW), and molasses was fed at 1.2g/kg BW. Compared to feed-grade urea, both sources of SRU decreased ruminal pH between 3 and 6h after dosing (P<0.05). At 3 and 9h after dosing and at 15 and 21h, both sources of slow-release urea reduced the rumen ammonia compared to urea (P<0.05). The two sources of slow-release urea did not improve the total tract or rumen digestibility of dry matter (DM) and neutral detergent fiber (NDF) or the rate of microbial protein synthesis in growing lambs fed low quality forage.

Effects of dietary level of selenium and grain on digestive metabolism in lambs

The objective was to evaluate the effect of different levels of selenium with two levels of grain corn in the diets on ruminal, postruminal, and total tract digestion of nutrients, ruminal fermentation characteristics, and selenium balance in lambs. A split-plot design was used in four periods with repeated Latin square using eight Suffolk &amp;times; Dorset male lambs with four levels of selenium (sodium selenite, Na&lt;sub&gt;2&lt;/sub&gt;SeO&lt;sub&gt;3&lt;/sub&gt;), without adding selenium, 0.3, 0.6, and 0.9 mg of selenium/kg dry matter (DM) with 70 and 50% of corn grain in the diet. The four selenium levels affected organic matter as follows: starch, neutral detergent fibre, nitrogen and selenium excretion; selenium ruminal digestion; organic matter, neutral detergent fibre, nitrogen and selenium postruminal digestion; and organic matter, neutral detergent fibre, nitrogen and selenium total tract digestion (P &amp;lt; 0.05). Starch and organic matter flow decreased with 0.6 and 0.9 mg of selenium with the 70% grain diet (P&amp;nbsp;&amp;lt; 0.05). Selenium flow increased linearly with selenium levels (P &amp;lt; 0.01) with both levels of grain. Selenium supplementation increased linearly selenium concentration in ruminal fluid (P &amp;lt; 0.01), but did not affect other ruminal characteristics. Also, selenium absorption and retention was increased by selenium concentrations (P&amp;nbsp;&amp;lt; 0.01). The apparent absorption of selenium increased (31%, P &amp;lt; 0.01) with the 70% grain diet. In conclusion, the high content of nonstructural carbohydrates improved the availability of selenium and 0.9 mg of selenium/kg &lt;br /&gt;DM improved the absorption and availability of selenium. &amp;nbsp;

Basal and hormone-stimulated metabolism in lambs varies with breed and diet quality

The present study investigated the effects of breed and diet quality on basal and hormone-stimulated energy metabolism in lambs. Twenty-four 7-mo-old merino (MM; n = 12) and second-cross (2X; n = 12) lambs were maintained indoors and fed ad libitum either a low-quality (7.8% crude protein [CP] and 8.1 MJ metabolizable energy [ME]/kg dry matter [DM]) or a moderate-quality (17.6% CP and 9.1 MJ ME/kg DM) diet in a crossover design. After 3 wk of feeding, lambs were injected intravenously with insulin (10 μg/kg body weight [BW]) and epinephrine (0.8 μg/kg BW) on consecutive days and blood samples were collected at −30, −15, −1, 3, 6, 10, 15, 20, 30, 45, 60, 90, and 120 min relative to time of injection. Lambs fed the low-quality diet had lower DM ( P < 0.001), CP ( P < 0.01), and ME ( P < 0.001) intakes than lambs fed the moderate-quality diet. Baseline nonesterified fatty acid (NEFA) concentrations were higher ( P < 0.001) in lambs fed a low-quality diet than in those fed a moderate-quality diet but there were no breed differences. Second-cross lambs had higher basal plasma concentrations of glucose ( P < 0.001), lactate ( P < 0.001), and cortisol ( P < 0.02) than the MM lambs, although there was no effect of diet on any of these plasma variables. Insulin injection caused a rapid hypoglycemic response in all lambs but the response was more pronounced ( P < 0.01) in MM lambs compared with 2X lambs. The cortisol response to insulin was twice as great ( P < 0.05) in MM lambs compared with 2X lambs. There was a rebound in plasma NEFA concentrations after approximately 30 min postinjection that was most pronounced ( P < 0.01) in MM lambs. Epinephrine injection caused a rapid increase in plasma NEFA, which tended to be lower in lambs fed the moderate-quality diet ( P = 0.07) than in those fed the low-quality diet, but did not differ between breeds. Epinephrine injection caused rapid hyperglycemia, with the response being lower ( P < 0.006) in lambs fed the moderate-quality diet compared with those fed the low-quality diet and greater ( P < 0.050) in 2X than in MM lambs. Epinephrine injection caused a rapid increase in plasma lactate that tended to be greater ( P = 0.07) in 2X lambs compared with MM lambs. The present study demonstrated clear breed differences in basal and hormone-stimulated metabolism, such that the 2X lambs appeared to be less sensitive to insulin and more sensitive to epinephrine than the MM lambs. These metabolic differences may be related to the fundamental differences in physiology that are associated with meat and wool production from 2X and MM breeds, respectively. They may also be related to adaptation of the MM breed to harsh environments through the ability of the body to metabolize fat resources, which are an efficient source of energy for survival.

Desempenho, características da carcaça, digestibilidade aparente dos nutrientes, metabolismo de nitrogênio e parâmetros ruminais de cordeiros alimentados com rações contendo polpa cítrica úmida semidespectinada e/ou polpa cítrica desidratada

O objetivo neste estudo foi avaliar os efeitos da substituição parcial da polpa cítrica desidratada (PCD) pela polpa cítrica úmida semidespectinada in natura (PCUD), silagem de polpa cítrica úmida semidespectinada (PCUDS) ou silagem de polpa cítrica úmida semidespectinada adicionada de benzoato de sódio (PCUDS+B) sobre o desempenho, as características da carcaça, a digestibilidade aparente dos nutrientes, os parâmetros ruminais e o metabolismo de nitrogênio. Na avaliação de desempenho, 64 cordeiros Santa Inês foram alimentados com rações contendo 95% de concentrado e 5% de bagaço de cana-de-açúcar in natura durante 56 dias. O delineamento experimental utilizado foi o de blocos completos casualizados (BCC). A dieta controle continha 69,5% de PCD e foi substituída em 30% na matéria seca (MS) pela PCUD, PCUDS ou PCUDS+B. Não houve diferença no consumo de MS, no ganho médio diário de peso e nas características das carcaças. No entanto, a eficiência alimentar dos cordeiros alimentados com PCUD foi maior que a daqueles alimentados com PCD. No ensaio de metabolismo, 16 borregos Santa Inês, canulados no rúmen, foram distribuídos em BCC e alimentados com rações contendo 85% de concentrado e 15% de bagaço de cana-de-açúcar in natura. A dieta controle continha 75,3% de PCD e foi substituída em 30% na MS pela PCUD, PCUDS ou PCUDS+B. Não houve diferença nos coeficientes de digestibilidade da MS, matéria orgânica e proteína bruta. O coeficiente de digestibilidade da fibra em detergente neutro, porém foi maior para a PCUD comparado à PCD. A concentração de amônia no fluido ruminal foi maior para as rações contendo PCD em comparação àquelas com PCUDS e PCUDS+B. No entanto, para os demais parâmetros ruminais não foi verificado efeito dos tratamentos. A PCUD in natura ou ensilada pode substituir parcialmente a PCD em rações com alta proporção de concentrado para cordeiros em confinamento.

Effect of whole-crop pea (Pisum sativum L.) silages differing in condensed tannin content as a substitute for grass silage and soybean meal on the performance, metabolism, and carcass characteristics of lambs

Two experiments were conducted to investigate the effect of inclusion of whole-crop pea (WCP) silages, differing in condensed tannin content, as a substitute for grass silage (GS) and soybean meal on lamb metabolism, performance, plasma metabolites, digestibility, and carcass characteristics. In both experiments lambs were offered either solely GS or a 50:50 mix on a DM basis of GS with either low-tannin (LTPS) or high-tannin (HTPS) pea silage ad libitum. Each forage mix was fed with either 400 g/d of low-protein (LP) concentrate or 400 g/d of LP with an additional 200 g/d of pelletized soybean meal (HP), resulting in 6 dietary treatments. Experiment 1 examined the effects of the diets on metabolism, digestibility, and N balance using 6 lambs in 4 periods of 21 d in an incomplete crossover design. Experiment 2 used 48 lambs and examined the effects of the diets on ADG, plasma metabolites, and carcass characteristics over 56 d. Both experiments were analyzed using a 3 × 2 factorial arrangement of treatments. In Exp. 1, lambs offered the LTPS diets had a greater (P < 0.05) digestibility of DM and OM than those offered the GS diets. Lambs offered the WCP silages had an increased (P < 0.05) N intake, N output, and digestibility of GE compared with those offered GS. Mean N digestibility was greatest (P < 0.05) in lambs offered LTPS. Lambs offered HP diets had increased (P < 0.001) digestibility of DM, OM, GE and N, and N- intake, output, retention, and digestibility compared with those offered the LP diets. In Exp. 2, there was no effect (P > 0.05) of forage type on intake, slaughter BW, or feed conversion efficiency (FCE). However, lambs offered the LTPS had a greater (P < 0.05) ADG than those offered the GS diets. Feeding diets containing HP increased (P < 0.001) total DMI, slaughter BW, ADG, and FCE. Lambs offered the WCP had a greater (P < 0.05) plasma β-hydroxybutyrate and urea concentration compared with those offered the GS diets. Feeding lambs HP diets increased (P < 0.05) plasma urea and total protein. Forage mix had no effect (P > 0.05) on carcass composition except for fat depth, which was greater (P < 0.05) in lambs offered WCP silage. Diets containing the HP increased (P < 0.05) carcass weight, hind leg circumference, chop dimensions, and kidney weight. It was concluded that lambs offered LTPS performed better than those offered GS and that LTPS has a concentrate sparing effect. Additionally, the increased tannin concentration in HTPS did not increase performance over lambs offered either GS or LTPS.

Feeding sunflower oil to partially defaunate the rumen increases nitrogen retention, urea-nitrogen recycling to the gastrointestinal tract and the anabolic use of recycled urea-nitrogen in growing lambs

The objective of the present study was to delineate how interactions between feeding sunflower oil (SFO) to partially defaunate the rumen and altering dietary ruminally fermentable carbohydrate may alter urea-N kinetics and N metabolism in lambs. In a 4 × 4 Latin square with a 2 × 2 factorial arrangement of treatments, four Suffolk ram lambs (61·5 (se 4·0) kg) were used. Treatments were 0 ( - SFO) v. 6 % (+SFO) SFO and dry-rolled barley (DRB) v. pelleted barley (PB). N balance was measured over 4 d, with concurrent measurement of urea-N kinetics using continuous intra-jugular infusions of [(15)N(15)N]urea. Feeding SFO decreased (P = 0·001) ruminal protozoa and NH3-N concentrations. Urinary N excretion was lower (P = 0·003), and retained N was higher (P = 0·002) in +SFO lambs compared with - SFO lambs. Endogenous production of urea-N (urea-N entry rate; UER) was similar across treatments. Urea-N transfer to the gastrointestinal tract (GIT) (GIT entry rate; GER), expressed as absolute amounts (16·4 v. 13·1 g/d) or as a proportion of the UER (0·693 v. 0·570), its anabolic use (9·0 v. 6·0 g/d) and microbial N supply (14·6 v. 10·9 g/d) were higher (P ≤ 0·001) in +SFO lambs compared with -SFO lambs. As a proportion of the UER, GER was higher, whereas urinary urea-N loss was lower, in lambs fed PB compared with those fed DRB (P = 0·01). In summary, feeding SFO increased urea-N recycling to the GIT and microbial non-NH(3)-N supply, thus providing new evidence that the improved efficiency of N utilization in partially defaunated ruminants could be partly mediated by an increase in urea-N recycling.

Activities of biotransformation enzymes and flubendazole metabolism in lambs (Ovis aries): effect of gender and flubendazole therapy

The effect of flubendazole (FLU) therapy on in vitro FLU biotransformation and the activities of selected biotransformation enzymes were investigated in male and female lambs. Four experimental groups were used: control (untreated) ewes and rams and FLU-treated ewes and rams (orally, 15mg/kg per day, for three consecutive days). Subcellular fractions were prepared from liver and intestinal mucosa 24h after the final dosage was administered. Activities of cytochromes P450 (CYP), flavine mono-oxygenases (FMO), carbonyl reducing enzymes, UDP-glucuronosyl transferase (UGT) and glutathione S-transferase were tested. Significant gender differences were observed for FMO-mediated activity (2-fold higher in ram lambs) and UGT activity (up to 30% higher in ewe lambs), but no gender differences were observed in FLU metabolism. FLU-treatment of lambs moderately changed the activities of some CYPs, FMO, and UGT in liver microsomes. In vitro FLU reduction was not altered in the liver, but was slightly higher in the small intestine of FLU pre-treated lambs. This correlated with the higher carbonyl reductase activities measured in the gut mucosa of these animals.

Effects of Chromium on Energy Metabolism in Lambs Fed with Different Dietary Protein Levels

The effects of chromium (Cr), dietary crude protein (CP) level, and potential interactions of these two factors were investigated in term of energy metabolism in lambs. Forty-eight 9-week-old weaned lambs (DorperxSmall-tail Han sheep, male, mean initial body weight = 22.96 kg±2.60 kg) were used in a 2x3 factorial arrangement of supplemental Cr (0 μg/kg, 400 μg/kg or 800 μg/kg from chromium yeast) and protein levels (low protein: 157 g/d to 171 g/d for each animal, or high protein: 189 g/d to 209 g/d for each animal). Blood samples were collected at the beginning and end of the feeding trial. The lambs were then sacrificed and tissue samples were frozen for further analysis. Chromium at 400 μg/kg decreased fasting insulin level and the ratio of plasma insulin to glucagon, but these differences were not statistically significant; in contrast, chromium at 800 μg/kg increased the ratio significantly (p<0.05). Protein at the high level increased plasma tumor necrosis factor α (TNF-α) level (p = 0.060). Liver glycogen content was increased significantly by Cr (p<0.05), which also increased liver glucose-6-phosphatase (G-6-Pase) and adipose hormone-sensitive lipase (HSL) activity. At 400 μg/kg, Cr increased muscle hexokinase (HK) activity. High protein significantly increased G-6-Pase activities in both the liver (p< 0.05) and the kidney (p<0.05), but significantly decreased fatty acid synthase (FAS) activity in subcutaneous adipose tissue (p<0.05). For HSL activity in adipose tissue, a Cr×CP interaction (p<0.05) was observed. Overall, Cr improved energy metabolism, primarily by promoting the glycolytic rate and lipolytic processes, and these regulations were implemented mainly through the modulation by Cr of the insulin signal transduction system. High protein improved gluconeogenesis in both liver and kidney. The interaction of Cr×CP indicated that 400 μg/kg Cr could reduce energy consumption in situations where energy was being conserved, but could improve energy utilization when metabolic rate was increased.