Dietary Starch Content Research Articles

Nutritional Assessment of 67 Potato Cultivars Grown in China Using the Nutrient-Rich Foods Index Model

The nutritional properties of tubers from 67 potato (Solanum tuberosum L.) cultivars were systematically evaluated in this study. The Nutrient-Rich Foods (NRF) Index Model was adopted for nutrient profiling and assessing the overall nutrient density of potatoes. The macronutrients including: dry matter, crude protein, total dietary fiber (TDF), crude fat, starch, and ash contents were found to be in the range of 14.8–30.5 g/100 g fresh weight (FW), 5.71–12.0, 1.99–3.39, 0.18–1.08, 56.0–75.5, and 3.02–6.06 g/100 g dry weight (DW), respectively. Furthermore, vitamin C, macro-mineral K and micro-mineral Fe contents ranged between 22.6–86.6, 1518–3145, and 1.42–6.07 mg/100 g dry weight (DW), respectively. According to the NRF Index model (NRF11.3), NRF11.3 score ranged between 70.6–110 for male and 110–115 per 100 kcal for female aged ≥18 years old. As a consequence, the described NRF11.3 index model could be used to determine the major components and micronutrients of different potato cultivars and aid in comprehensive nutritional study on potato as a desirable staple to human nutrition and daily diet.

Effect of high dietary starch levels on growth, hepatic glucose metabolism, oxidative status and immune response of juvenile largemouth bass, Micropterus salmoides

An experimental trial was conducted to investigate the effects of high dietary starch levels on growth, hepatic glucose metabolism enzyme, antioxidant capacity and immune responses of largemouth bass, Micropterus salmoides. Fish (initial body weight: 16.9 ± 0.24 g) were fed three isonitrogenous and isoenergetic semi-purified diets containing 5%, 10% and 20% wheat starch, respectively. The results indicated that fish fed 5% and 10% starch diets showed significantly better weight gain, specific growth rate (SGR), protein efficiency ratio (PER) and feed conversion ratio (FCR) compared with that fed 20% starch diet. Meanwhile, fish fed 20% starch diet had a significantly higher hepatic glycogen and muscle glycogen contents than those fed the other diets. The alanine amiotransferase (ALT) and aspartate transaminase (AST) activities, glucose and insulin contents in plasma increased significantly with dietary starch levels, whereas triglyceride content showed the opposite trend. In addition, the highest glucokinase (GK), pyruvate kinase (PK) and phosphofructokinase (PFK) activities in liver were also observed in fish fed 20% starch diet. However, both fructose-1,6-bisphosphatase (FBPase) and pyruvate carboxylase (PC) activities in liver decreased significantly as dietary starch levels increased. Moreover, the lower superoxide dismutase (SOD) and catalase (CAT), the higher malondialdehyde (MDA) contents in liver were observed in fish fed 20% starch diets. Compared to the 5% and 10% starch, the 20% starch could enhance the content of plasma nitric oxide (NO) and the activities of inducible nitric oxide synthase (iNOS) and alkaline phosphatase (ALP). Results demonstrate that the starch levels may affect growth performance and metabolic changes, which suggest that high-starch diets were inefficiently used as an energy source by M. salmoides juveniles. Excessive dietary starch contents could result in oxidative stress, suppress innate immunity, and thus affect the health status of M. salmoides.

Effect of supplemental yeast culture and dietary starch content on rumen fermentation and digestion in dairy cows

The objectives of this experiment were to evaluate the effect of feeding a culture of Saccharomyces cerevisiae on rumen metabolism and digestibility when cows are fed diets varying in starch content. Four lactating Holstein cows were assigned to a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Treatments were low starch (LS; 23% of diet DM) and no yeast culture (YC; LS-control), LS and 15 g of YC/d (LS-YC), high starch (HS; 29% of diet DM) and no YC (HS-control), and HS and 15 g of YC/d (HS-YC). Periods lasted 28 d, with the last 9 d for data collection. Days 20 to 24 were used to determine production, nutrient flow, and digestibility. On d 25, 3 kg of corn grain DM was placed in the rumen 1 h before the morning feeding, and yields of milk and milk components were measured after the challenge. Blood was sampled -1, 3, 7, and 11 h relative to the morning feeding on d 24 and 25. Rumen pH was measured continuously on d 24 and 25. Rumen papillae were collected on d 24 and 28 to quantify mRNA expression of select genes. Supplementing YC increased yields of milk (26.3 vs. 29.6 kg/d), energy-corrected milk (ECM; 26.5 vs. 30.3 kg/d), fat (0.94 vs. 1.08 kg/d), true protein (0.84 vs. 0.96 kg/d), and ECM/dry matter intake (1.15 vs. 1.30) compared with the control but did not affect dry matter intake (22.6 vs. 22.9 kg/d). Cows fed HS had increased milk true protein percentage (3.18 vs. 3.31%) and yield (0.87 vs. 0.94 kg/d) compared with cows fed LS. Feeding HS-YC increased the proportion of dietary N incorporated into milk true protein from 24.9% in the other 3 treatments to 29.6%. Feeding HS increased the concentration of propionate (21.7 vs. 32.3 mM) and reduced that of NH3-N (8.3 vs. 6.7 mg/dL) in rumen fluid compared with the control, and combining HS with YC in HS-YC tended to increase microbial N synthesis compared with LS-YC (275 vs. 322 g/d). Supplementing YC to cows fed HS reduced plasma haptoglobin and rumen lactate concentrations, increased mean rumen pH, reduced the time with pH <6.0, and prevented the decrease in rumen neutral detergent fiber digestion caused by HS. Cows fed HS had less total-tract digestion of organic matter (73.9 vs. 72.4%) because of reduced acid detergent fiber (57.6 vs. 51.7%) and neutral detergent fiber (60.9 vs. 56.7%) digestibility. Production performance after the challenge was similar to that before the challenge, and YC improved yield of ECM. After the challenge, supplementing YC tended to reduce rumen lactate concentration compared with the control and reduced haptoglobin in cows fed HS. Feeding HS but not YC increased expression in rumen papillae of genes for receptors (FFAR2 and FFAR3) and transporter (SLC16A3) of short-chain fatty acids but did not affect genes involved in transport of Na+/H+ or water or in inflammatory response. Supplementing YC to dairy cows improved lactation performance in diets containing low or high starch, and mechanisms might be partially attributed to improvements in rumen pH, digestion of fiber, microbial N synthesis, and reduction in acute phase response.

Responses of fresh cows to three feeding strategies that reduce starch levels by feeding beet pulp.

The study objective was to evaluate the effects of reducing dietary starch content in fresh cow diets while maintaining NDF levels by substituting barley grain (BG), corn silage (CS), or both with beet pulp (BP) on nutrient digestion, ruminal fermentation, DMI, lactation performance, meal patterns, chewing activity, and sorting behavior. Thirty-six multiparous cows were randomly assigned to 1 of 4 experimental diets from calving to 21 d in lactation. Experimental diets were a high-starch diet with ground BG (CO; 24.9% starch; 0% BP) and 3 low-starch diets: the CO with BP substituted for ground BG (BB; 19.6% starch; 7% BP), the CO with BP substituted for CS (BC; 20.6% starch; 12% BP), or the CO with BP substituted for CS and ground BG (BCB; 20.3% starch; 12% BP). The CO, BB, BC, and BCB contained 33.4, 34.4, 32.9, and 33.7% NDF, respectively, and 23.1, 22.0, 18.2, and 19.2% forage NDF, respectively. There was no effect of diet on total tract nutrient digestibility ( > 0.20), ruminal pH ( = 0.49), or total VFA ( = 0.39). However, diets affected molar proportions of propionate and acetate ( ≤ 0.01). Relative to CO cows, the molar propionate percentage was less in BB cows ( < 0.01) and tended to be greater in BC cows ( = 0.10), whereas the molar percentage of acetate was less in BC cows than in BB ( < 0.01) and CO cows ( = 0.02). Relative to CO cows (16.50 kg/d), DMI was greater for BC (17.70 kg/d; < 0.01) and BCB cows (17.50 kg/d; = 0.01), but it was less in BB cows (15.60 kg/d; = 0.02). Similar to DMI results, milk yields tended to be greater for BC (37.89 kg/d; = 0.08) and BCB cows (37.81 kg/d; = 0.09) compared with CO cows (35.41 kg/d), but BB cows (33.05 kg/d) tended to produce less milk than CO cows ( = 0.1). Milk fat content tended to be less in BC ( = 0.08) and BCB cows ( = 0.10) than in CO cows. There was no effect of diet on eating and rumination patterns ( ≥ 0.18), except shortened meal intervals for BC and BCB cows compared with CO cows ( = 0.02). Dietary treatments did not affect chewing activities per day or bout ( = 0.50), but BC and BCB cows spent less time on chewing activities per kilogram DM ( < 0.01) and NDF intake ( < 0.01) compared with CO cows. Cows fed the BC and BCB sorted for long particles (>19 mm; < 0.01) but against particles < 1.18 mm ( < 0.01). In the present study, propionate did not seem to play a central role in feed intake regulation of fresh cows, because BB cows had depressed DMI and the lowest molar proportion of propionate. However, reducing starch levels in fresh cow diets by replacing CS and both CS and BG with BP positively affected DMI and milk yield.

Analysis of selected rumen microbial populations in dairy heifers limit fed diets varying in trace mineral form and starch content

Eight rumen-cannulated Holstein heifers were used to explore the effect of trace mineral form and diet starch content on selected ruminal microbial populations under limit feeding conditions. Heifers were subjected to a split-plot, 4×4 Latin square design with 19-day periods. Trace mineral form [organic proteinates (OTM) or inorganic sulfates (ITM)] was the whole-plot factor, and starch content (3.5%, 12.9%, 22.3%, and 31.7% DM) was the sub-plot factor. Rumen samples were collected 3h after feeding on day 18 of each period, and DNA was extracted. Relative abundances of 6 well-studied bacterial taxa, total anaerobic fungi, ciliate protozoa, methanogenic Archaea and bacteria were determined using validated primer sets by real-time quantitative PCR. Targeted populations had relative abundances comparable to those previously reported. Of the microbial populations measured, trace mineral form influenced only Prevotella bryantii, which was increased by OTM. Increasing dietary starch concentration linearly decreased methanogenic Archaea, total bacteria, Prevotella spp., and Prevotella bryantii, and tended to linearly decrease fungi and protozoa. In conclusion, contrary to the starch content, trace mineral form had limited impact on the abundance of selected microbial populations in limit fed heifers 3h after feeding. The unexpected effect of starch content on bacterial populations and protozoa could be the result of different eating patterns of heifers fed diets varying in starch content.

Suitable dietary starch source and supplementation level for largemouth bass ( Micropterus salmoides )

PDF HTML阅读 XML下载 导出引用 引用提醒 大口黑鲈饲料中适宜的淀粉源及添加水平 DOI: 作者: 作者单位: 上海海洋大学 水产与生命学院, 上海 201306 作者简介: 刘子科(1989-),男,硕士研究生,研究方向为水产动物营养与饲料科学.E-mail:657079084@qq.com 通讯作者: 中图分类号: S963 基金项目: 上海市科委地方院校能力建设项目（10320503100）；水产动物遗传育种中心上海市协同创新中心项目（ZF1206）. Suitable dietary starch source and supplementation level for largemouth bass (Micropterus salmoides) Author: Affiliation: College of Fisheries and Life Sciences, Shanghai Ocean University, Shanghai 201306, China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以4种淀粉，蜡质玉米淀粉（L）、高直链玉米淀粉（Z）、小麦淀粉（X）和木薯淀粉（M），分别以5%和10%的添加量配制了8种等氮和等能（CP 48%，GE 18.5 MJ/kg）的饲料（L5、L10、Z5、Z10、X5、X10、M5和M10）。用上述饲料饲养初始体重为（23.46±0.19）g的大口黑鲈45 d，以评定大口黑鲈饲料的适宜淀粉源及添加水平。结果显示，饲料中淀粉的添加水平和淀粉源对大口黑鲈的生长、饲料利用、体组成和非特异性免疫指标均有显著影响。随着同一种淀粉的添加量从5%升至10%，L10、X10和M10组实验鱼的特定生长率和摄食率显著降低，但饲料效率和蛋白质效率显著升高，而Z5和Z10组间的上述指标的差异不显著；L10、X10和M10组的肝体比、脏体比和肝糖原含量均显著升高，但Z5和Z10组间的脏体比差异不显著；全鱼和肝的脂肪含量及肝的蛋白质含量均显著降低；L10组的红细胞数和红细胞压积、Z10组的血清甘油三酯及X10组的红细胞压积和血清甘油三酯水平显著降低；Z10组的血清补体活性显著降低；L5、Z5、X5和M5组的餐后3~12 h的血糖水平各自低于L10、Z10、X10和M10组。不同的淀粉源在相同的添加量的情况下，Z5组的淀粉表观消化率和肝体比显著地低于L5、X5和M5组，而脂肪沉积率显著高于L5、X5和M5组；M5组的蛋白质表观消化率显著低于L5、Z5和X5组；Z10组的淀粉表观消化率、肝体比、脏体比和肝糖原含量显著低于L10、X10和M10组，而脂肪沉积率显著高于L10、X10和M10组；M10组的蛋白质表观消化率显著低于L10、Z10和X10组。饲料中淀粉的添加水平和淀粉源对大口黑鲈的摄食率、特定生长率、蛋白质消化率、脂肪沉积率、肝体比、肝糖原含量、红细胞数、血清甘油三酯含量和血清补体活性均有显著的交互作用。本研究表明，饲料的淀粉源和水平对大口黑鲈的生长、体组成、血液学指标、餐后血糖和非特异性免疫指标均有不同程度的影响，饲料中添加5%的蜡质玉米淀粉、高直链玉米淀粉、小麦淀粉和木薯淀粉均无妨碍，但添加10%的淀粉水平唯有高直链玉米淀粉较为合适。 Abstract:Eight iso-nitrogenous and iso-energetic (crude protein, 48% and gross energy, 18.5 MJ/kg) diets (L5, L10, Z5, Z10, X5, X10, M5, and M10) were formulated with 5% and 10% waxy corn starch (L), high-amylose corn starch (Z), wheat starch (X), and cassava starch (M) to determine a suitable starch source and supplementation level for a largemouth bass, , diet. Fish (initial body weight, 23.46 g±0.19 g) were fed to apparent satiation twice daily for 45 d. The results showed that the supplemented dietary starch level and starch source had significant effects on growth, feed utilization, body composition, and non-specific immunological indices of largemouth bass. Significant decreases in specific growth rate and feed intake were observed with increasing content of the same starch from 5% to 10%. However, feed and protein efficiency increased significantly in the L10, X10, and M10 groups, compared with those in the L5, X5 and M5 groups, whereas no differences were detected in these parameters between the Z5 and Z10 groups. Hepatosomatic index, viscerosomatic index, and liver glycogen concentration increased significantly in the L10, X10, and M10 groups, compared with those in the L5, X5, and M5 groups, but no difference was found in the viscerosomatic index between the Z5 and Z10 groups Whole-body and liver lipid contents, as well as liver protein content decreased significantly when any of the supplemented starches were increased from 5% to 10% in the diets. Blood erythrocyte count and hematocrit in the L10 group, serum triglyceride content in the Z10 group, and hematocrit and serum triglyceride content in the X10 group decreased significantly, compared with those in the L5, Z5, and X5 groups. Serum 50% hemolytic complement (CH50) activity was significantly lower in the Z10 group than that in the Z5 group. Serum glucose concentrations from 3 to 12 h after a meal in the L5, Z5, X5, and M5 groups were lower than those in the L10, Z10, X10, and M10 groups. Apparent digestibility of the dietary starch and hepatosomatic index were significantly lower in the Z5 group compared with those in the L5, X5, and M5 groups, whereas whole-body lipid deposition rate increased significantly. Apparent digestibility of dietary protein was significantly lower in the M5 group than that in the L5, Z5, and X5 groups. Apparent digestibility of dietary starch, hepatosomatic index, viscerosomatic index, and liver glycogen concentration decreased significantly in the Z10 group compared with those in the L10, X10, and M10 groups, whereas whole-body lipid deposition rate increased significantly. Apparent digestibility of dietary protein was significantly lower in the M10 group than that in the L10, Z10, and X10 groups. Significant interactions were detected between feeding rate, specific growth rate, protein digestion rate, lipid deposition rate, hepatosomatic index, glycogen content, erythrocyte count, serum triglyceride level, and serum CH50 activity between the dietary starch supplementation level and starch source. In conclusion, the starch source and supplementation level in the largemouth bass diet exerted different effects on growth performance, body composition, hematological parameters, non-specific immunological indices, and serum glucose. Adding 10% high-amylose corn starch was the most appropriate supplement in the diet for largemouth bass. 参考文献 相似文献 引证文献

Pre- and post-pellet whole grain inclusions enhance feed conversion efficiency, energy utilisation and gut integrity in broiler chickens offered wheat-based diets

In order to investigate whole grain feeding strategies seven dietary treatments were offered to 8 replicates (6 birds per cage) of male Ross 308 chicks from 7 to 28days post-hatch. A steam-pelleted, wheat-based diet in which the wheat had been ground through a 3.2mm hammer-mill screen served as the control. Whole wheat was added at 4.5, 9.0 and 18.0% of the diet in substitution for ground wheat and whole wheat was incorporated into the ration either pre- or post-pelleting. For post-pelleting additions, whole wheat and pelleted concentrate were blended. The effects of dietary treatments on relative gizzard and pancreas weights, gizzard contents and their pH and the incidence of dilated proventriculi were assessed. Treatment effects on growth performance and nutrient utilisation (AME as MJ/kg and MJ/day, ME:GE ratios, N retention and AMEn) were determined. Effects of treatments on starch and protein (N) digestibility coefficients and disappearance rates in the distal ileum were investigated on the basis of inherent AIA dietary concentrations and starch concentrations in the distal ileum were considered. Feed and water intakes and dry matter of excreta over the total excreta collection period were determined. Post-pellet inclusions of whole wheat had greater impacts on bird performance than whole wheat additions prior to pelleting. Relative to the ground grain control diet, post-pellet whole wheat inclusions increased relative gizzard weights, reduced gizzard digesta pH, reduced the incidence of dilated proventriculi, improved feed conversion ratios, ostensibly increased starch digestibility coefficients and disappearance rates in the distal ileum and reduced residual starch concentrations in the distal ileum. Additionally, post-pellet whole wheat inclusions unequivocally enhanced all nutrient utilisation parameters. Collectively, post-pellet whole wheat inclusion increased relative gizzard weights by 26.1% (18.35 versus 14.55g/kg; P<0.001), reduced the incidence of dilated proventriculi from 8.4 to 0.7% (P<0.02), improved FCR by 4.25% (1.442 versus 1.506; P<0.003), increased AME by 0.81MJ (12.88 versus 12.07MJ/kg; P<0.005)) and enhanced ME:GE ratios by 6.14% (0.743 versus 0.700; P<0.005). The 18.0% pre-pellet inclusion of whole grain increased relative gizzard weights by 13.0% (16.44 versus 14.55g/kg; P<0.005), improved FCR by 5.51% (1.423 versus 1.506; P<0.001) and enhanced AME by 0.59MJ (12.66 versus 12.07MJ/kg; P<0.005). This study confirms the advantages of whole grain feeding in the context of broiler chicken performance which appeared to be driven by greater extents of starch digestion allied to heavier relative gizzard weights.

Milling and extrusion of six barley varieties, effects on dietary fibre and starch content and composition

Barley is a rich source of dietary fibre that can promote beneficial physiological effects. The carbohydrate composition in different barley varieties differs considerably and choice of variety is thus important. This study examined whether differences in carbohydrate composition observed in barley kernels of different varieties persisted in the sifted flour and in an extruded product. Six barley varieties were milled and extruded and dietary fibre and starch in the kernels, flour and extruded product were analysed. The starch content was found to be higher in flour and extruded product than in kernels. The content of arabinoxylan was higher in sifted flour than in kernels, but was decreased by extrusion. The extractability of arabinoxylan was increased by extrusion, while its average molecular weight was decreased. Extrusion also decreased the content of mixed-linkage (1 → 3),(1 → 4)-β-D-glucan in all varieties, but increased its extractability. The six barley varieties were affected in much the same way by milling and extrusion, but clear differences could still be observed. For example, the arabinoxylan in variety SW 28708 was less affected and variety KVL 301 had much lower extractability (76% vs 91–98%) of mixed-linkage (1 → 3),(1 → 4)-β-D-glucan after extrusion than the other varieties.

Effects of dietary resistant starch content on nutrient and energy digestibility and fecal metabolomic profile in growing pigs1

Effects of dietary resistant starch content on nutrient and energy digestibility and fecal metabolomic profile in growing pigs1

Methane and nitrous oxide emissions from Canadian dairy farms and mitigation options: An updated review

This review examined methane (CH4) and nitrous oxide (N2O) mitigation strategies for Canadian dairy farms. The primary focus was research conducted in Canada and cold climatic regions with similar dairy systems. Meta-analyses were conducted to assess the impact of a given strategy when sufficient data were available. Results indicated that options to reduce enteric CH4from dairy cows were increasing the dietary starch content and dietary lipid supplementation. Replacing barley or alfalfa silage with corn silage with higher starch content decreased enteric CH4per unit of milk by 6%. Increasing dietary lipids from 3% to 6% of dry matter (DM) reduced enteric CH4yield by 9%. Strategies such as nitrate supplementation and 3-nitrooxypropanol additive indicated potential for reducing enteric CH4by about 30% but require extensive research on toxicology and consumer acceptance. Strategies to reduce emissions from manure are anaerobic digestion, composting, solid–liquid separation, covering slurry storage and flaring CH4, and reducing methanogen inoculum by complete emptying of slurry storage at spring application. These strategies have potential to reduce emissions from manure by up to 50%. An integrated approach of combining strategies through diet and manure management is necessary for significant GHG mitigation and lowering carbon footprint of milk produced in Canada.

Effect of Dietary Starch Source and Concentration on Equine Fecal Microbiota.

Starch from corn is less susceptible to equine small intestinal digestion than starch from oats, and starch that reaches the hindgut can be utilized by the microbiota. The objective of the current study was to examine the effects of starch source on equine fecal microbiota. Thirty horses were assigned to treatments: control (hay only), HC (high corn), HO (high oats), LC (low corn), LO (low oats), and LW (low pelleted wheat middlings). Horses received an all-forage diet (2 wk; d -14 to d -1) before the treatment diets (2 wk; d 1 to 14). Starch was introduced gradually so that horses received 50% of the assigned starch amount (high = 2 g starch/kg BW; low = 1 g starch/kg BW) by d 4 and 100% by d 11. Fecal samples were obtained at the end of the forage-only period (S0; d -2), and on d 6 (S1) and d 13 (S2) of the treatment period. Cellulolytics, lactobacilli, Group D Gram-positive cocci (GPC), lactate-utilizers and amylolytics were enumerated. Enumeration data were log transformed and analyzed by repeated measures ANOVA. There were sample day × treatment interactions (P < 0.0001) for all bacteria enumerated. Enumerations from control horses did not change during the sampling period (P > 0.05). All treatments except LO resulted in increased amylolytics and decreased cellulolytics, but the changes were larger in horses fed corn and wheat middlings (P < 0.05). Feeding oats resulted in increased lactobacilli and decreased GPC (P < 0.05), while corn had the opposite effects. LW had increased lactobacilli and GPC (P < 0.05). The predominant amylolytic isolates from HC, LC and LW on S2 were identified by 16S RNA gene sequencing as Enterococcus faecalis, but other species were found in oat fed horses. These results demonstrate that starch source can have a differential effect on the equine fecal microbiota.

BOARD-INVITED REVIEW: Efficiency of converting digestible energy to metabolizable energy and reevaluation of the California Net Energy System maintenance requirements and equations for predicting dietary net energy values for beef cattle.

For the past several decades, nutrient requirement systems for beef cattle in North America have recommended that dietary ME can be calculated as dietary DE × 0.82, but considerable published data suggest a variable relationship between DE and ME. We reviewed the literature and tabulated the results of 23 respiration calorimetry studies (87 treatment mean data points), in which measurements of fecal, urinary, and gaseous energy were determined with beef cattle (bulls, steers, and heifers) and growing dairy cattle. Mixed-model regression analyses to adjust for the effects of the citation from which the data were obtained suggested a strong linear relationship between ME and DE (Mcal/kg of DM; ME = 0.9611 × DE - 0.2999; = 0.986, root mean square error [RMSE] = 0.048, < 0.001 for intercept, slope ≠ 0). Analysis of residuals from this simple linear regression equation indicated high correlations of residuals with other dietary components, and a slight increase in precision was obtained when dietary CP, ether extract, and starch (% of DM) concentrations were included in a multiple linear regression equation (citation-adjusted = 0.992, RMSE = 0.039). Using the simple linear relationship, we reevaluated the original data used to develop the California Net Energy System (CNES) for beef cattle by recalculating ME intake and heat production and regressing the logarithm of heat production on ME intake (both per BW, kg daily). The resulting intercept and slope of the recalculated data did not differ ( ≥ 0.34) from those reported for the original analyses of the CNES data, suggesting that use of the linear equation for calculating ME concentration was consistent with NEm and NEg values as derived in the CNES. Nonetheless, because the cubic equations recommended by the NRC to calculate dietary NEm and NEg from ME were based on conversion of DE to ME using 0.82, these equations were mathematically recalculated to account for the linear relationship between DE and ME. Overall, our review and analyses suggested that there is a strong linear relationship between DE and ME, which seems to be consistent across a wide range of dietary conditions, cattle types, and levels of intake. Applying this linear relationship to predict ME concentrations agreed with the original CNES calculations for NE requirements, thereby allowing the development of new equations for predicting dietary NEm and NEg values from ME.

Effects of reducing dietary starch content by replacing barley grain with wheat dried distillers grains plus solubles in dairy cow rations on ovarian function

Our objective was to evaluate the effects of dietary starch content, altered by partial substitution of dietary grain with wheat dried distillers grain with solubles (DDGS), on the interval from calving to first ovulation, concentrations of hormones and metabolites in plasma and follicular fluid, and granulosa cell gene expression in preovulatory follicles. Sixty lactating dairy cows were assigned to 1 of 2 diets from calving until 84d postpartum. Diets were formulated to contain either 17.3% rolled barley grain (29.2% starch) or 17.2% wheat DDGS (19.1% starch), with 43.0% barley silage and 21.6% rolled corn grain as the other major ingredients (dry matter basis). Transrectal ultrasonography was performed twice weekly to monitor ovarian dynamics from 7±2d postpartum until ovulation or until 56d in milk, whichever occurred earlier. Plasma concentrations of insulin and insulin-like growth factor-1 (IGF-1) were determined in all 60 cows, and that of glucose, fatty acids, and urea in a subset of 24 cows, representing those in which the first ovulation occurred spontaneously within 5 wk postpartum. Estradiol (proestrus) and progesterone (12d postovulation) in plasma were also measured. Concentrations of insulin, IGF-1, glucose, fatty acids, and urea were determined in follicular fluid (wk 9), and the expression of LH receptor, estrogen receptor β, cytochrome P450 aromatase, and plasma type glutathione peroxidase genes measured in granulosa cells obtained from the preovulatory follicles at wk 9 postpartum in the subset of 24 cows. Diets did not alter the interval from calving to first ovulation (32.3±2.5d), but a significantly lower proportion of cows on the DDGS diet (20%) ovulated multiple (≥2) follicles at the first ovulation than those on the barley grain diet (40%). The incidence of multiple ovulations tended to be lower at first insemination (10 vs. 21% for cows fed DDGS and barley grain diets, respectively). Mean plasma concentration of insulin was higher in cows fed the barley grain diet (2.5 vs 1.6 IU/mL), and a diet by time interaction was noted, with cows on the barley grain ration having higher insulin from wk 6 to 12 postpartum; however, mean plasma IGF-1 concentration did not differ between dietary groups. In the subsets, mean plasma concentrations of metabolites or estradiol and progesterone were not affected by diet, parity, or diet by parity interactions. Cows on the DDGS diet had lower concentrations of IGF-I (69 vs. 108 ng/mL) and higher fatty acids (222 vs. 149mEq/L) in the follicular fluid obtained from preovulatory follicles. Diet, parity, and diet by parity interactions did not affect the concentrations of insulin, glucose, urea, estradiol, and progesterone in follicular fluid. Diets did not alter the expression profiles of LHr, estrogen receptor β, CYP19, and GPx3 genes in granulosa cells. In summary, diets did not affect the interval from calving to first ovulation or granulosa cell gene expression. However, reducing dietary starch content by a partial replacement of dietary grain with wheat DDGS increased fatty acids in follicular fluid and reduced the concentrations of insulin in plasma, IGF-1 in follicular fluid, and the incidence of multiple ovulations.

Effects of dietary resistant starch content on metabolic status, milk composition, and microbial profiling in lactating sows and on offspring performance.

In the present study, the effects of dietary resistant starch (RS) content on serum metabolite and hormone concentrations, milk composition, and faecal microbial profiling in lactating sows, as well as on offspring performance was investigated. Sixteen sows were randomly allotted at breeding to two treatments containing low- and high-RS contents from normal and high-amylose corn varieties, respectively, and each treatment had eight replicates (sows). Individual piglet body weight (BW) and litter size were recorded at birth and weaning. Milk samples were obtained on day 10 after farrowing for composition analysis. On day 2 before weaning, blood and faecal samples were collected to determine serum metabolite and hormone concentrations and faecal microbial populations, respectively. Litter size at birth and weaning were not influenced (p>0.05) by the sow dietary treatments. Although feeding the RS-rich diet to sows reduced (p=0.004) offspring birth BW, there was no difference in piglet BW at weaning (p>0.05). High-RS diet increased (p<0.05) serum triacylglycerol and nonesterified fatty acid concentrations and milk total solid content, and tended (p=0.09) to increase milk fat content in lactating sows. Feeding the RS-rich diet to sows increased (p<0.01) faecal bacterial population diversity. These results indicate that high-RS diets induce fatty acid mobilization and a greater intestinal bacterial richness in lactating sows, as well as a greater nutrient density in maternal milk, without affecting offspring performance at weaning.

Relative contribution of ruminal buffering systems to pH regulation in feedlot cattle fed either low- or high-forage diets

The relative contribution of ruminal short-chain fatty acid (SCFA) absorption and salivary buffering to pH regulation could potentially change under different dietary conditions. Therefore, the objective of this study was to investigate the effects of altering the ruminal supply of rapidly fermentable carbohydrate (CHO) on absorptive function and salivation in beef cattle. Eight heifers (mean BW±SD=410±14 kg) were randomly allocated to two treatments in a crossover design with 37-day periods. Dietary treatments were barley silage at 30% low forage (LF) or 70% high forage (HF) of dietary dry matter (DM), with the remainder of the diet consisting of barley grain (65% or 25% on a DM basis) and a constant level (5%) of supplement. The LF and HF diets contained 45.3% and 30.9% starch, and 4.1% and 14.0% physically effective fiber (DM basis), respectively. Ruminal pH was continuously measured from day 17 to day 23, whereas ruminal fluid was collected on day 23 to determine SCFA concentration. Ruminal liquid passage rate was determined on day 23 using Cr-ethylenediaminetetraacetic acid. Eating or resting salivation was measured by collecting masticate (days 28 and 29) or saliva samples (days 30 and 31) at the cardia, respectively. On days 30 and 31, the temporarily isolated and washed reticulo-rumen technique was used to measure total, and Cl−-competitive (an indirect measure of protein-mediated transport) absorption of acetate, propionate and butyrate. As a result of the higher dietary starch content and DM intake, the ruminal supply of rapidly fermentable CHO, total ruminal SCFA concentration (118 v. 95 mM; P<0.001) and osmolality (330 v. 306 mOsm/kg; P=0.018) were greater in cattle fed LF compared with HF. In addition, feeding LF resulted in a longer duration (2.50 v. 0.09 h/day; P=0.02) and a larger area (0.44 v. 0.01 (pH×h)/day; P=0.050) that pH was below 5.5. There was no diet effect on total and Cl−-competitive absorption (mmol/h and %/h) of acetate, propionate, butyrate and total SCFA (acetate+propionate+butyrate), but eating salivation was less (131 v. 152 ml/min; P=0.02), and resting salivation tended to be less (87 v. 104 ml/min; P=0.10) in cattle fed an LF diet. In summary, lower ruminal pH in cattle with greater rapidly fermentable CHO intake was attributed to an increase in SCFA production and decrease in salivation, which were not compensated for by an increase in epithelial permeability.

Feeding of wheat bran and sugar beet pulp as sole supplements in high-forage diets emphasizes the potential of dairy cattle for human food supply

Besides the widely discussed negative environmental effects of dairy production, such as greenhouse gas emissions, the feeding of large amounts of potentially human-edible feedstuffs to dairy cows is another important sustainability concern. The aim of this study was therefore to investigate the effects of a complete substitution of common cereal grains and pulses with a mixture of wheat bran and sugar beet pulp in a high-forage diet on cow performance, production efficiency, feed intake, and ruminating behavior, as well as on net food production potential. Thirteen multiparous and 7 primiparous mid-lactation Holstein dairy cows were randomly assigned to 1 of 2 treatments in a change-over design with 7-wk periods. Cows were fed a high-forage diet (grass silage and hay accounted for 75% of the dry matter intake), supplemented with either a cereal grain-based concentrate mixture (CON), or a mixture of wheat bran and dried sugar beet pulp (WBBP). Human-edible inputs were calculated for 2 different scenarios based on minimum and maximum potential recovery rates of human-edible energy and protein from the respective feedstuffs. Dietary starch and neutral detergent fiber contents were 3.0 and 44.1% for WBBP, compared with 10.8 and 38.2% in CON, respectively. Dietary treatment did not affect milk production, milk composition, feed intake, or total chewing activity. However, chewing index expressed in minutes per kilogram of neutral detergent fiber ingested was 12% lower in WBBP compared with CON. In comparison to CON, the human-edible feed conversion efficiencies for energy and protein, defined as human-edible output per human-edible input, were 6.8 and 5.3 times higher, respectively, in WBBP under the maximum scenario. For the maximum scenario, the daily net food production (human-edible output minus human-edible input) increased from 5.4MJ and 250g of crude protein per cow in CON to 61.5MJ and 630g of crude protein in the WBBP diet. In conclusion, our data suggest that in forage-based dairy production systems, wheat bran and sugar beet pulp could replace common cereal grains in mid-lactation dairy cows without impairing performance, while strongly increasing human-edible feed conversion efficiency and net food production index.

Effect of increasing dietary nonfiber carbohydrate with starch, sucrose, or lactose on rumen fermentation and productivity of lactating dairy cows

The objective of this study was to investigate effects of increasing dietary nonfiber carbohydrate (NFC) with starch, sucrose, or lactose on rumen fermentation, volatile fatty acid absorption, and milk production of lactating dairy cows. Twenty-eight multiparous, lactating Holstein cows (141±50 d in milk; 614±53kg of body weight) including 8 ruminally cannulated cows were used in this study. Cows were assigned to 4 dietary treatments in a 4×4 Latin square design with 21-d periods. The treatments were control [27% starch and 4% sugar on a dry matter (DM) basis], a high-NFC diet by increasing dietary starch content (STA; 32% starch and 4% sugar on a DM basis), and 2 more high-NFC diets by increasing dietary sugar content (27% starch and 9% sugar on a DM basis) in which sucrose (SUC) or lactose (LAC) was supplemented. Dry matter intake was greater for cows fed high-NFC diets compared with control diet (27.1 vs. 26.3kg/d), but rumen pH and milk production did not differ between cows fed control and high-NFC diets. However, cows fed high-disaccharide diets had lower mean rumen pH than those fed STA diet (6.19 vs. 6.32). Although molar proportion of butyrate was greater for high-disaccharide treatments than STA treatment (15.2 vs. 13.7 mol/100 mol), absorption rate of volatile fatty acid in the rumen was not affected by treatment. In addition, cows fed high-disaccharide diets had higher energy-corrected milk yield than cows fed STA diet (39.6 vs. 38.0kg/d). Dry matter intake did not differ between cows fed 2high-disaccharide diets. Although cows fed the SUC diet had lower molar proportion of butyrate in the rumen compared with those fed the LAC diet (14.4 vs. 15.9 mol/100 mol), the SUC diet did not decrease rumen pH. In addition, cows fed the SUC diet had lower nutrient digestibility of organic matter than did those fed the LAC diet (59.7 vs. 64.4%), but milk component yields did not differ between the 2 high-disaccharide diet treatments. The results of the present study suggested that partially replacing dietary starch with disaccharides increased DM intake and energy-corrected milk, although rumen pH decreased for high-disaccharide diets, and that the rumen pH responses cannot be attributed to difference in absorption rate of volatile fatty acids in the rumen. In addition, type of sugars affected nutrient digestibility and rumen fermentation, but the effects were not large enough to affect rumen pH and milk production.

Milk production responses to a change in dietary starch concentration vary by production level in dairy cattle

The effects of dietary starch concentration on yield of milk and milk components were evaluated in a crossover design experiment. Holstein cows (n=32; 115±22 d in milk) with a wide range in milk yield (28 to 62kg/d) were assigned randomly within level of milk yield to a treatment sequence. Treatments were diets containing 30% dry ground corn (CG) or 30% soyhulls (SH) on a DM basis. Diets containing corn silage and alfalfa silage were formulated to contain 16% crude protein, 24% forage neutral detergent fiber, and either 27 or 44% neutral detergent fiber and 30 or 12% starch for CG and SH, respectively. Cows were fed a diet intermediate to the treatments during a preliminary 14-d period. Treatment periods were 28 d with measurements taken throughout the period for energy calculations and the final 5 d used for data and sample collection for production variables. Compared with SH, CG increased dry matter intake, and yields of milk, milk protein, milk fat, and energy-corrected milk, as well as milk protein concentration. Treatment did not affect milk fat concentration. Yield of de novo synthesized and preformed milk fatty acids increased with CG. Treatment interacted with level of preliminary milk production for several response variables (yields of milk, milk protein, milk fat, energy-corrected milk, and 3.5% fat-corrected milk). Compared with SH, the CG treatment increased energy-corrected milk in higher-producing cows with a lesser response to CG as milk yield decreased. The CG treatment increased milk:feed compared with the SH treatment, but not body weight or body condition score. In conclusion, higher-producing cows benefited from the high-starch diet, and lower-producing cows were able to maintain production when most of the starch was replaced with nonforage fiber.

Starch and lipid in diets for douradoSalminus brasiliensis(Cuvier 1816): growth, nutrient utilization and digestive enzymes

Carbohydrates and lipids are the major and cheaper non-protein energy sources for fish diets. This study aimed at determining ideal relationship between dietary starch and lipids and their influence on digestive enzyme profile of juvenile dourado. Trials were set up in a closed-loop system with controlled temperature, dissolved oxygen, pH and total ammonia. Experimental extruded diets formulated to contain different starch (St) to lipids (Lip) ratio (St : Lip = 0 : 1, 0.3 : 1, 0.7 : 1, 1.0 : 1, 1.4 : 1, 2.0 : 1, 2.3 : 1 to 3.3 : 1) were fed to juvenile dourado (3.34 ± 0.16 g) and stocked into 30 polyethylene tanks (330 L, 30 fish per tank) in a completely randomized design with unbalanced repetition (n = 3 or 4), in two daily meals (1000 and 1530) until satiation, for 95 days. Dietary starch contents higher than 145.2 g kg-1 (St : Lip > 1.0 : 1.0) hampered the performance of fish, but, paradoxically, the inclusion of carbohydrates in the diet elicited better utilization of dietary protein and energy by the species. Fish adapted digestive enzyme profile to dietary starch contents through increasing secretion of alkaline proteases and non-specific lipases, but secretion of amylase was not altered. Physiological responses show the limitation of species on the use of dietary carbohydrates.

Performance of early-lactation dairy cows as affected by dietary starch and monensin supplementation

The objective of this study was to evaluate the effect of postpartum dietary starch content and monensin supplementation throughout the periparturient period and into early lactation on production performance of dairy cows during early lactation. Prior to parturition, primiparous (n=21) and multiparous (n=49) Holstein cows were fed a common controlled-energy close-up diet with a daily topdress of either 0 or 400mg/d monensin. From d 1 to 21 postpartum, cows were fed a high-starch (HS; 26.2% starch, 34.3% NDF, 22.7% ADF, 15.5% CP) or low-starch (LS; 21.5% starch, 36.9% NDF, 25.2% ADF, 15.4% CP) total mixed ration with a daily topdress of either 0mg/d of monensin or 450mg/d monensin (MON), continuing with prepartum topdress treatment assignment. From d 22 through 63 postpartum, cows were fed HS and continued with their assigned daily topdress. Interactions of starch content and MON supplementation were not significant for any of the variables measured. Cows fed HS from wk 1 to 3 postpartum had higher early-lactation milk yields (starch × week interaction) compared with LS cows, but HS cows also had lower percentages of milk fat, true protein, lactose, and total solids during the same period, resulting in similar yields of energy-corrected milk (ECM) between starch treatments. Cows fed HS had higher early-lactation dry matter intake (DMI; starch × week interaction) and lost less body condition score during wk 1 to 3, contributing to improved energy balance postpartum. No effect of starch treatment was observed on apparent total-tract dry matter or starch digestibilities assessed during d 18 to 19 (±2) postpartum, although cows fed the LS diet had greater apparent total-tract NDF digestibility compared with cows fed the HS diet. Cows fed MON had higher DMI and higher milk yields during the first 9 wk of lactation. However, all cows had similar yields of ECM because of trends for lower milk fat content during early lactation. In part because of similar yields of ECM between these treatments and higher DMI for cows fed MON, ECM per DMI during the first 9 wk of lactation was not affected by MON treatment. There was no effect of MON treatment on apparent total-tract dry matter, NDF, or starch digestibilities. Overall, cows fed more propiogenic diets in early lactation (HS or MON) had increased milk yield and DMI during the immediate postpartum period, indicating that diets with greater propiogenic capacity do not have detrimental effects on early-lactation DMI.