Influence of Different Ratios of Cobalt and Copper Supplementation on Vitamin B_(12) Status and Nutrient Utilization in Sheep

The present study is aimed to investigate the effects of different ratios of cobalt （Co） and copper （Cu） supplementation on vitamin B12 status and nutrient utilization in sheep. Twenty wether lambs with an average weight （22.9 ± 0.8） kg were randomly divided into five groups and fed with the control diet which was supplied with 0.3 mg kg^-1 DM （dry matter） of Co to the basal diet, and four supplemental diets which were supplied either 0.3 or 0.6 mg kg^-1 DM of Co and 10 or 20 mg kg^-1 DM of Cu to the basal diet, respectively for 8 wk. The supplementation of Co and Cu with different levels improved plasma vitamin B12 concentration which was increased with feeding time, but stable after 6 wk. Vitamin B12 status was accounted for Co intake with no combined effects by supplementation of different levels of Co and Cu. The plasma concentrations of methylmalonic acid, homocysteine, folic acid, and glucose did not show the consistent results with plasma vitamin B12, which was considered to be resulted from Cu action. Addition of Co and Cu with different levels had no influence on digestibility of dry matter （DM）, organic matter （OM）, crude protein （CP） and nitrogen free （NFE）, and N metabolism （P〉 0.05）, but the digestibility of fat and fibre （P〈0.01） was enhanced by supplementation of 0.3 mg kg^-1 DM of Co and 20 mg kg^-1 DM of Cu. In conclusion, the supplementation of Co and Cu with different levels has no influence on vitamin B12 status. The optimum ratio of Co and Cu in diet could enhance the nutrient utilization.

Beneficial effects of a decreased meal frequency on nutrient utilization,secretion of luteinizing hormones and ovarian follicular development in gilts

Background:Replacement gilts are typically fed ad libitum,whereas emerging evidence from human and rodent studies has revealed that time-restricted access to food has health benefits.The objective of this study was to investigate the effect of meal frequency on the metabolic status and ovarian follicular development in gilts.Methods:A total of 36 gilts(Landrace×Yorkshire)with an age of 150±3 d and a body weight of 77.6±3.8 kg were randomly allocated into one of three groups(n=12 in each group),and based on the group allocation,the gilts were fed at a frequency of one meal(T1),two meals(T2),or six meals per day(T6)for 14 consecutive weeks.The effects of the meal frequency on growth preference,nutrient utilization,short-chain fatty acid production by gut microbial,the post-meal dynamics in the metabolic status,reproductive hormone secretions,and ovarian follicular development in the gilts were measured.Results:The gilts in the T1 group presented a higher average daily gain(+48 g/d,P<0.05)and a higher body weight(+4.9 kg,P<0.05)than those in the T6 group.The meal frequency had no effect on the apparent digestibility of dry matter,crude protein,ether extract,ash,and gross energy,with the exception that the T1 gilts exhibited a greater NDF digestibility than the T6 gilts(P<0.05).The nitrogen balance analysis revealed that the T1 gilts presented decreased urine excretion of nitrogen(−8.17 g/d,P<0.05)and higher nitrogen retention(+9.81 g/d,P<0.05),and thus exhibited higher nitrogen utilization than the T6 gilts.The time-course dynamics of glucose,α-amino nitrogen,urea,lactate,and insulin levels in serum revealed that the T1 group exhibited higher utilization of nutrients after a meal than the T2 or T6 gilts.The T1 gilts also had a higher acetate content and SCFAs in feces than the T6 gilts(P<0.05).The age,body weight and backfat thickness of the gilts at first estrous expression were not affected by the meal frequency,but the gilts in the T1 group had higher levels of serum luteinizing hormone on the 18th day of the 3rd estrus cycle and 17β-estradiol,a larger number of growing follicles and corpora lutea,and higher mRNA expression levels of genes related to follicular development on the 19th day of the 3rd estrus cycle.Conclusions:The current findings revealed the benefits of a lower meal frequency equal feed intake on nutrient utilization and reproductive function in replacement gilts,and thus provide new insights into the nutritional strategy for replacement gilts,and the dietary pattern for other mammals,such as humans.

Light regulation of horticultural crop nutrient uptake and utilization

Plants demonstrate dynamic changes in molecular structures under fluctuating light conditions.Accumulating evidence suggests that light plays a vital role in plant growth and morphogenesis.In particular,light has a role in the absorption and utilization of nutrients in plants.Despite significant progress in understanding the mechanism of nutrient acquisition and assimilation,how light affects and regulates ion uptake remains a question.Studies in model plants,Arabidopsis thaliana,suggest that light affects the nutrient utilization in roots through a complex regulatory network;nonetheless,the molecular mechanisms underlying the various effects of light on these processes in crop plants remain fragmentary.In this review,we discuss the light effects(light quality,light intensity,and photoperiod)on nutrient uptake and utilization in horticultural crops for optimizing crop productivity and increasing fertilizer use efficiency.

Effects of Different Nitrogen Levels on Growth and Nitrogen Utilization of Sugarcane

[Objectives]To systematically study the effects of different nitrogen levels on the growth and nitrogen utilization of sugarcane in Guangxi.[Methods]Through field experiment and indoor analysis,different nitrogen application levels were set up to determine soil nitrogen content and sugarcane nitrogen content.The effects of different nitrogen levels on sugarcane yield,agronomic characters and nitrogen utilization were studied.[Results]The effect of nitrogen application rate on sugarcane yield showed a quadratic curve,and nitrogen application could significantly increase sugarcane yield,and the sugarcane yield reached the maximum when the nitrogen application rate reached 714 kg/ha.[Conclusions]With the increase of nitrogen application rate,sugarcane yield increased,but when it exceeded a certain range,the sugarcane yield decreased significantly.

The Nutrient Expert decision support system improves nutrient use efficiency and environmental performance of radish in North China

Excessive fertilization has led to nutrient use inefficiency and serious environmental consequences for radish cultivation in North China.The Nutrient Expert(NE)system is a science-based,site-specific fertilization decision support system,but the updated NE system for radish has rarely been evaluated.This study aims to validate the feasibility of NE for radish fertilization management from agronomic,economic,and environmental perspectives.A total of 46 field experiments were conducted over four seasons from April 2018 to November 2019 across the major radish growing regions in North China.The results indicated that NE significantly reduced N,P_(2)O_(5),and K_(2)O application rates by 98,110,and 47 kg ha^(-1) relative to those in the farmers’practice(FP),respectively,and reduced N and P_(2)O_(5) inputs by 48 and 44 kg ha^(-1),respectively,while maintaining the same K_(2)O rate as soil testing(ST).Relative to FP and ST,NE significantly increased radish yield by 2.7 and 2.6 t ha^(-1)(4.2 and 4.0%)and net returns by 837 and 432 USD ha^(-1),respectively.On average,NE significantly improved the agronomic efficiency(AE)of N,P,and K(relative to FP and ST)by 42.4 and 31.0,67.4 kg kg^(-1) and 50.9,and 20.3 and 12.3 kg kg^(-1);enhanced the recovery efficiency(RE)of N,P,and K by 11.4 and 7.0,14.1 and 7.5,and 11.3 and 6.3 percentage points;and increased the partial factor productivity(PFP)of N,P,and K by 162.9 and 96.8,488.0 and 327.3,and 86.9 and 22.4 kg kg^(-1),respectively.Furthermore,NE substantially reduced N and P_(2)O_(5) surpluses by 105.1 and 115.1 kg ha^(-1),respectively,and decreased apparent N loss by 110.8 kg ha^(-1) compared to FP.These results indicated that the NE system is an effective and feasible approach for improving NUE and promoting cleaner radish production in North China.

Mycorrhizal Networks Interacting with Litter Improves Nutrients and Growth for One Plant through the Vary of N/P Ratio under Karst Soil

Arbuscular mycorrhizae(AM)fungi affect nutrient uptake for host plants,while it is unclear how AM fungi interacting with soil litter affect plant growth and nutrient utilization through mycorrhizal networks in karst soil of deficient nutrients beyond the rhizosphere.An experiment was conducted in a microcosm composed of a planting compartment for Cinnamomum camphora seedlings with or without Glomus mosseae fungus(M+vs.M−)and an adjacent litter compartment containing or not containing additional litter material of Arthraxon hispidus(L+vs.L−),where the compartments are connected either by nylon mesh of 20μm or 0.45μm which either allow available mycorrhizal networks within the litter compartment or prevent mycelium entering into the litter compartment(N+vs.N−).Plant biomass and nutrients were measured.The results showed that the addition of litter changed the symbiotic process in mycorrhizal colonization,spore,and hyphal density,which when in association with the host plant then affected the biomass,and accumulations of N(nitrogen)and P(phosphorus)in the individual plant as well as root,stem,and leaf respectively.AM fungi increased N and P accumulations and N/P ratio in individual plants and plant tissues.A decrease of the N/P ratio of the individual plant was observed when AM fungus interacted significantly with litter through mycorrhizal networks in the litter compartment.The results indicate that the C.camphora seedlings benefited from litter in nutrient utilization of N and P through the vary of N/P ratio when accessing mycorrhizal networks.These findings suggest that mycorrhizal networks interacting with litter improve growth and nutrients of N and P for plants through the vary of N/P ratio in order to alleviate nutrient limitation under karst soil.

Evaluating Feed Intake of Fishes in Aquaculture Nutrition Experiments with Due Consideration of Mortality and Fish Survival

Mortality is normal and natural in aquaculture experiments. However, it becomes a problem when measuring feed intake as a component of nutrient utilization parameters such as： feed conversion ratio, feed conversion efficiency, apparent net protein utilization, protein efficiency ratio and protein productive value. In order to accurately evaluate feed intake with due consideration of mortality encountered, a formulae was developed using empirical data obtained from an experiement that had mortality. The formulae Fwas： total feed consumed by numbers of survived fishes=DL∑i=1n（Fi/Ni）N. Where, D=Numbers of days fishes were fed within each period ibefore it was adjusted（e.g fortnight）, it was constant throught period of experiment; F=Uantity of feed fed per day for a fortnight before the quantity was adjusted, it changed every fortnight; L=Numbers of living fishes at the end of experimental period; N=Numbers of fishes at each weighing period, it might change every fortnight or might be constant if no mortality occurred; while n=Numbers of times fishes were weighed and quantity of feed was adjusted but this did not include the final weighing at the termination of experiment. However, if the fishes were weighed weekly, then D=6.

Effects of Dietary Replacement of Maize with Sweet Potato Peel in the Diet of African Catfish Clarias gariepinus(Burchell,1822)

This study was carried out to evaluate the effects of dietary replacement of maize with sweet potato peel in the diet of Clarias gariepinus juveniles.The levels of the SPP inclusion in the experimental diets were 0%,25%,50%,75%and 100%.All the diets were iso-nitrogenous.One hundred and fifty(150)C.gariepinus juveniles(33 g~35 g)were randomly distributed to five treatments with three replicates each and 5%of their body weight for 12 weeks.Fish carcass proximate compositions analyzed before and after feeding with the experimental diets shows that CP and EE differed significantly(p<0.05)among the experimental fish and the control,except the percentage CP of the fish fed SPP0%and SPP50%in which there was no significant difference(p>0.05).Highest MWG of 207.70±25.95 g was obtained in the fish fed SPP100%followed by 191.30±16.15 g obtained in the fish fed SPP75%.The least MWG of 149.83±16.01 g was recorded in fish fed SPP25%.The highest FCR of 3.61±0.45 g was recorded in the fish fed SPP100%.A steady decrease in FCR was observed with decreasing inclusion levels of SPP meal.However,higher FW,FL,SGR and PER were observed in the experimental fish as from 50%inclusion levels of the SPP.The cost of feed per kg was reduced and the NP and WG increased with increasing levels of SPP and the profitability was enhanced at 100%SPP inclusion level.The results revealed that C.gariepinus juvenile could tolerate up to 50%,75%and 100%inclusion levels of SPP.The best growth performance was recorded in the fish fed SPP100%,therefore,sweet potato peel can replace maize in the diet of C.gariepinus without any inauspicious effect on the growth performance and nutrient utilization.

Water and Nutrient Use Efficiency in Diploid, Tetraploid and Hexaploid Wheats

Three diploid （Triticum boeoticum, AA; Aegilops speltoides, BB and Ae. tauschii, DD）, two tetraplold （T. dlcoccoides, AABB and T. dicoccon, AABB） and one hexapioid （T. vulgare, AABBDD） varieties of wheat, which are very important In the evolution of wheat were chosen in this study. A pot experiment was carried out on the wheat under different water and nutrient conditions （i） to understand the differences in biomass, yield, water use efficiency （WUE）, and nutrient （N, P and K） use efficiency （uptake and utilization efficiency） among ploidies in the evolution of wheat; （li） to clarify the effect of water and nutrient conditions on water and nutrient use efficiency; and （ill） to assess the relationship of water and nutrient use efficiency in the evolution of wheat. Our results showed that from diploid to tetraplold then to hexaploid during the evolution of wheat, both root biomass and above-ground biomass Increased Initially and then decreased. Water consumption for transpiration decreased remarkably, correlating with the decline of the growth period, while grain yield, harvest index, WUE, N, P and K uptake efficiency, and N, P and K utilization efficiency Increased significantly. Grain yield, harvest index and WUE decreased In the same order： T. vulgare 〉 T. dicoccon 〉 T. dicoccoides 〉 Ae. tauschii 〉 Ae. speltoides 〉 T. boeoticum. Water stress significantly decreased root blomass, above-ground biomass, yield, and water consumption for transpiration by 47-52%, but remarkably Increased WUE. Increasing the nutrient supply increased wheat above-ground biomass, grain yield, harvest Index, water consumption for transpiration and WUE under different water levels, but reduced root blomass under drought conditions. Generally, water stress and low nutrient supply resulted in the lower nutrient uptake efficiency of wheat. However, water and nutrient application had no significant effects on nutrient utilization efficiency, suggesting that wheat nutrient utilization efficiency is mainly controlled by genotypes. Compared to the other two diploid wheats, Ae. squarrosa （DD） had significant higher WUE and nutrient utilization efficiency, Indicating that the D genome may carry genes controlling high efficient utilization of water and nutrient. Significant relation- ships were found between WUE and N, P and K utilization efficiency.

Utilization of autoclaved and fermented sesame(Sesamum indicum L.) seed meal in diets for Til-aqua natural male tilapia

Current research emphasis has been on the reduction of feed cost by incorporating processed sesame seed meal in the diet of tilapia. Raw sesame(Sesamum indicum) seed was soaked and subjected to either autoclaving or fermentation, after which their oil contents were mechanically extracted. Graded levels of autoclaved(71.2,165,5 and 296.3 g/kg designated as diets 1, 2 and 3, respectively) and fermented(71.0,164.3 and 292,2 g/kg designated as diets 4, 5 and 6, respectively) sesame seed meal were included into fishmeal based diets for Til-aqua natural male tilapia(NMT) fry(initial weight,1.69 ± 0.02 g), A diet without sesame seed meal served as the control. Diets were approximately iso-nitrogenous(35% crude protein). Fish were fed 5 times their maintenance requirement, which was 3.2 x 5 x [fish weight(g)/1,000]^(0.8) daily for 56 days. Processing improved the nutritional profile of raw sesame seed meal in terms of its crude protein and antinutrient compositions. Growth performance of fish was similar(P> 0.05) in the control and dietary treatments. The group fed diet 3 exhibited significantly poorer feed conversion ratio(1.14), protein efficiency ratio(2.77) and economic conversion ratio(US$1.38/kg) relative to the group that received diet 5. Apparent digestibility coefficients for protein, lipid and energy in diet 3 were similar(P > 0.05) to those in diet 6 but significantly lower(P < 0.05) than those of the control and other dietary groups. The sesame seed meals processed with different methods did not significantly affect crude protein, crude lipid and gross energy compositions in the fish carcass. The study demonstrated that71.2 g/kg of autoclaved and 164.3 g/kg of fermented sesame seed meal could be incorporated in the diet of Til-aqua NMT with cost benefit.

The aquaporin MePIP2;7 improves MeMGT9-mediated Mg2+ acquisition in cassava

Aquaporins are important transmembrane water transport proteins which transport water and several neutral molecules. However, how aquaporins are involved in the synergistic transport of Mg2+and water remains poorly understood. Here, we found that the cassava aquaporin Me PIP2;7 was involved in Mg2+transport through interaction with Me MGT9, a lower affinity magnesium transporter protein. Knockdown of Me PIP2;7 in cassava led to magnesium deficiency in basal mature leaves with chlorosis and necrotic spots on their edges and starch over-accumulation. Mg2+content was significantly decreased in leaves and roots of Me PIP2;7-RNA interference(PIP-Ri) plants grown in both field and Mg2+-free hydroponic solution. Xenopus oocyte injection analysis verified that Me PIP2;7 possessed the ability to transport water only and Me MGT9 was responsible for Mg^(2+)effux.More importantly, Me PIP2;7 improved the transportability of Mg^(2+)via Me MGT9 as verified using the CM66 mutant complementation assay and Xenopus oocytes expressing system. Yeast twohybrid, bimolecular fuorescence complementation,co-localization, and co-immunoprecipitation assays demonstrated the direct protein–protein interaction between Me PIP2;7 and Me MGT9 in vivo. Mg2+fux was significantly elevated in Me PIP2;7-overexpressing lines in hydroponic solution through non-invasive micro-test technique analysis. Under Mg^(2+)-free condition, the retarded growth of PIP-Ri transgenic plants could be recovered with Mg^(2+)supplementation. Taken together, our results demonstrated the synergistic effect of the Me PIP2;7 and Me MGT9 interaction in regulating water and Mg2+absorption and transport in cassava.