Nitrogen Gain Research Articles

Red ginseng ameliorates lipotoxicity-induced renal fibrosis in hyperuricemia mice

Ethnopharmacological relevanceChronic kidney disease can be caused by numerous diseases including obesity and hyperuricemia (HUA). Obesity may exacerbate the renal injury caused by HUA. Red ginseng, a steamed products of Panax ginseng Meyer root, is known for its remarkable efficacy in improving metabolic syndrome, such as maintaining lipid metabolic balance. However, the role of red ginseng on hyperuricemia-induced renal injury in obese cases remains unclear. Aim of the studyThis study aimed to investigate the action of red ginseng extract (RGE) on lipotoxicity-induced renal injury in HUA mice. Materials and methodsA high-fat diet (HFD)-induced obesity model was employed to initially investigate the effects of RGE on body weight, TC, OGTT, renal lipid droplets, and renal function indices such as uric acid, creatinine, and urea nitrogen. Renal structural improvement was demonstrated by H&E staining. Subsequently, an animal model combining obesity and HUA was established to further study the impact of RGE on OAT1 and ACC1 expression levels. The mechanisms underlying renal injury regulation by RGE were postulated on the basis of RNA sequencing, which was verified by immunohistochemical (including F4/80, Ki67, TGF-β1, α-SMA, and E-cadherin), Masson, and Sirius red staining. ResultsRGE modulated HFD-induced weight gain, glucose metabolism, and abnormalities of uric acid, urea nitrogen, and creatinine. RGE alleviated the more severe renal histopathological changes induced by obesity combined with HUA, with down-regulated the protein levels of ACC1, F4/80, Ki67, TGF-β1, and α-SMA, and up-regulated OAT1 and E-cadherin. ConclusionsRGE has ameliorative effects on chronic kidney disease caused by obesity combined with HUA by maintaining lipid balance and reducing renal inflammation and fibrosis.

Nitrogen transformation dynamics in macrophyte-assisted high-rate vermifilter treating real domestic sewage

Due to economic and ecological sustainability, vermifiltration has become a popular alternative to conventional wastewater treatment methods. However, the science behind nitrogen removal in vermifiltration has yet to be adequately explored. Additionally, no study is available on assessing the performance of vermifilters/macrophyte-assisted vermifilters (VFs/MAVFs) at higher hydraulic loading rates (HLRs), which has been a significant loophole regarding the vermifiltration technology. The present study investigated the performance of a MAVF in terms of nitrogen transformation dynamics during the treatment of real domestic sewage subjected to higher HLRs. The designed MAVF ensured a decent removal of ammonium nitrogen (NH4+-N), total Kjeldahl nitrogen (TKN), organic nitrogen, and total nitrogen (TN). In contrast, there was a considerable gain in effluent nitrate nitrogen (NO3−-N) concentration than its influent concentration. The highest removal of NH4+-N (98.2 ± 0.7 %), TKN (99 ± 0.5 %), and organic nitrogen (100 %) corresponded to the experimental run with an influent COD of (200 ± 25) mg/L and HLR of (3 ± 0.1) m3/m2-d, whereas the experimental run with an influent COD of (200 ± 25) mg/L and HLR of (7 ± 0.2) m3/m2-d resulted in the maximum increase in effluent NO3−-N concentration (73 ± 10.6 times its influent concentration). The maximum TN removal of (87 ± 2.2) % was achieved for the experimental run with an influent COD of (700 ± 45) mg/L and HLR of (3 ± 0.1) m3/m2-d. The present research reinforces the suitability of MAVF technology as a cost-effective and ecologically benevolent bio-remediation alternative for domestic sewage.

Effect of Varying Levels and Source of Slow-release Urea Fertilizers on Yield, Post Harvest Soil Nutrient Status and Economics of Wet Direct Seeded Rice (Oryza sativa L.)

A field experiment was conducted at the research farm of ICAR-Indian Institute of Rice Research (IIRR), Hyderabad, Rajendranagar in kharif, 2022 to study the effect of varying levels and source of slow-release urea fertilizers on yield, post harvest soil nutrient status and economics of wet direct seeded rice. The experiment was laid out in a randomized block design with ten treatments consisting of nitrogen management practices and replicated thrice. The results revealed that 100% RDN (Recommended Dose of Nitrogen) (120 kg/ha) applied through silicon coated urea resulted in the highest grain yield (6249 kg/ha) and straw yield (7114 kg/ha). Post harvest soil nutrient status revealed that 125% recommended dose nitrogen (150 kg/ha) applied through silicon coated urea resulted in the highest soil available nitrogen. Similarly, the highest soil available nitrogen gain was recorded in the plots that received 125% silicon coated urea. Silicon coated urea applied @ 120 kg/ha ulimately fetched higher gross return of ₹. 1,42,964/ha, net returns ₹. 1,03,793 and benefit-cost ratio of 2.65. It can be concluded that RDN applied through silicon coated urea @ 120 kg/ha found to be a suitable alternative to neem coated urea in increasing the grain yield, soil fertility and profitability.

DL-methionyl-DL-methionine as an efficient methionine source for promoting zootechnical performance and methionine-related pathways in the whiteleg shrimp (Penaeus vannamei).

Methionine (MET) supplementation is a current strategy to achieve shrimp requirement. Notwithstanding, the efficiency of the precisely formulated feeds can be diminished since shrimps are slow eaters and masticate feed externally that results in nutrient leaching. In this regard, a methionine dipeptide (DL-methionyl DL-methionine) benefits the feed industry by reducing MET water solubility while increasing its bioavailability. Therefore, the effects of feeding whiteleg shrimp (Penaeus vannamei) with increasing levels of methionine dipeptide were evaluated on zootechnical performance and methionine-, immune- and antioxidant-related pathways. A 74 d growth trial was conducted by feeding a control diet and four diets supplemented with AQUAVI® Met-Met at 0·08, 0·12, 0·24 and 0·32% of DM. Diet digestibility, body amino acids (AA) composition and nitrogen metabolites, metabolic enzymes, oxidative status and gene expression were evaluated. It can be concluded that graded dietary increase of methionine dipeptide up to 0·24 % for 74 d translated in significant gains on the growth performance, feed efficiency, nutrient and nitrogen gain and shrimp survival. Moreover, it was showed that Met-Met dietary spare leads to an improvement of free-AA pool and nitrogen metabolites concentration and reduces the signs of oxidative stress. Finally, in a closer look to the MET-related pathways passive to be altered by Met-Met spare, a clear modulation of the described antioxidant and cell proliferation routes was detected.

Capture of mammal excreta by Nepenthes is an effective heterotrophic nutrition strategy.

While isotopic enrichment of nitrogen (15N) and carbon (13C) is often used to determine whether carnivorous plant species capture and assimilate nutrients from supplemental sources such as invertebrate prey or mammal excreta (heterotrophic nutrition), little is known about how successful the different strategies deployed by carnivorous plants are at obtaining supplemental nutrition. The collection of mammalian faeces by Nepenthes (tropical pitcher plants) is the result of a highly specialized biological mutualism that results in heterotrophic nitrogen gain; however, it remains unknown how effective this strategy is in comparison to Nepenthes species not known to collect mammalian faeces. We examined how isotopic enrichment varied in the diverse genus Nepenthes, among species producing pitchers for invertebrate capture and species exhibiting mutualisms for the collection of mammal excreta. Enrichment factors were calculated from δ15N and δ13C values from eight Nepenthes species and naturally occurring hybrids along with co-occurring reference (non-carnivorous) plants from three mountain massifs in Borneo: Mount Kinabalu, Mount Tambuyukon and Mount Trus Madi. All Nepenthes examined, except N. edwardsiana, were significantly enriched in 15N compared to co-occurring non-carnivorous plants, and 15N enrichment was more than two-fold higher in species with adaptations for the collection of mammal excreta compared with other Nepenthes. The collection of mammal faeces clearly represents a highly effective strategy for heterotrophic nitrogen gain in Nepenthes. Species with adaptations for capturing mammal excreta occur exclusively at high elevation (i.e. are typically summit-occurring) where previous studies suggest invertebrate prey are less abundant and less frequently captured. As such, we propose this strategy may maximize nutritional return by specializing towards ensuring the collection and retention of few but higher-value N sources in environments where invertebrate prey may be scarce.

Can Taurine Supplementation in a Diet with Soybean Meal Instead of Fish Meal Improve the Growth Performance, Feed Utilization, and Antioxidant Capacity of Spotted Knifejaw (Oplegnathus punctatus)?

To determine the impact of replacing fish meal (FM) in the diet with various levels of soybean meal (SBM) on the spotted knifejaw Oplegnathus punctatus, a 56 day feeding trial was done. Seven diets were formulated with SBM to replace 0% (SBM0), 30% (SBM30), 40% (SBM40), 50% (SBM50), 60% (SBM60), and 70% (SBM70) of FM protein, and SBM50 + T was developed on the basis of SBM50 with the addition of 1.2% taurine. There were triplicate groups of 18 fish (initial weight: 14.62 ± 0.02 g). The weight gain (WG), specific growth rate (SGR), feed efficiency (FE), and protein efficiency ratio (PER) values of the SBM0, SBM30, and SBM50 + T groups were found to be significantly higher than those of the SBM60 and SBM70 groups (p < 0.05). The daily energy gain (DEG), daily nitrogen gain (DNG), daily lipid gain (DLG), energy retention (ER), nitrogen retention (NR), and lipid retention (LR) values decreased significantly with increasing dietary SBM levels (p < 0.05). The highest retention of most amino acids (except lysine) was observed in the SBM30 group (p < 0.05). The lipid content of the whole body and dorsal muscle decreased significantly as dietary SBM levels increased (p < 0.05). Fish fed the SBM70 diet had the lowest serum triglyceride (TG) concentrations (p < 0.05). The effects of different treatments on total cholesterol (T-CHO) were not significant (p > 0.05). Fish fed the SBM0 and SBM30 diets had the highest amylase (AMS) and lipase (LPS) activities (p < 0.05). The lowest liver superoxide dismutase (SOD) and catalase (CAT) activities were observed in the SBM70 group. The malondialdehyde (MDA) concentration of the SBM50 to SBM70 groups were significantly higher than that of other groups (p < 0.05). The levels of interleukin 8 (il-8) mRNA were highest in fish fed the SBM0, SBM30, and SBM50 + T diets (p < 0.05), while the level of transforming growth factor β1 (tgf-β1) was the opposite (p < 0.05). According to the broken line regression of WG and FE, the highest level of FM substitution by SBM for Oplegnathus punctatus was 24.07–25.31%.

Agroecological Management and Increased Grain Legume Area Needed to Meet Nitrogen Reduction Targets for Greenhouse Gas Emissions

The nitrogen applied (N-input) to cropping systems supports a high yield but generates major environmental pollution in the form of greenhouse gas (GHG) emissions and losses to land and water (N-surplus). This paper examines the scope to meet both GHG emission targets and zero N-surplus in high-intensity, mainly cereal, cropping in a region of the Atlantic zone in Europe. A regional survey provides background to crops grown at an experimental farm platform over a run of 5 years. For three main cereal crops under standard management (mean N-input 154 kg ha−1), N-surplus remained well above zero (single year maximum 55% of N-input, five-year mean 27%), but was reduced to near zero by crop diversification (three cereals, one oilseed and one grain legume) and converted to a net nitrogen gain (+39 kg ha−1, 25 crop-years) by implementing low nitrification management in all fields. Up-scaling N-input to the agricultural region indicated the government GHG emissions target of 70% of the 1990 mean could only be met with a combination of low nitrification management and raising the proportion of grain legumes from the current 1–2% to at least 10% at the expense of high-input cereals. Major strategic change in the agri-food system of the region is therefore needed to meet GHG emissions targets.

Temporal Variation of Nitrogen and Carbon Mineralizations of Different Organic Materials

ABSTRACT Farmyard manure, vermicompost and leonardite materials are widely used to improve soil fertility. However, studies determining the effect of these organic materials on soil carbon and nitrogen gain at different times after mixing them with the soil are limited. This study was conducted to determine the effects of increased doses of leonardite, vermicompost, and farmyard manure (0, 20, 40, and 60 tons ha−1) on soil nitrogen concentration and carbon cycle at different incubation times (0, 15, 30, 45, 60, and 90 days) after they were mixed into the soil. Analysis results of soil samples taken during six different incubation periods showed that organic matter amount in the soil, total nitrogen (N), and nitrogen components (NO3 –NH4 +) varied significantly depending on the type of material applied, the amount of application, and the residence time of the material in the soil. The most significant increases in the amount of the soil organic matter were determined on the 90th day of mixing 40 tons of ha−1 vermicompost into the soil, on the 60th day of mixing 40 tons of ha−1 leonardite into the soil, and on the 30th day of mixing 60 tons of ha−1 farmyard manure into the soil. The highest values in terms of soil total nitrogen concentration was observed on the 60th day of application of 60 tons of ha−1 leonardite to the soil, on the 15th day of application of 60 tons of ha−1 vermicompost, and on the 45th day of application of 40 tons of ha−1 farmyard manure. As a result, it was determined that the positive effect of increased doses of organic material on soil characteristics increased with prolonging of incubation time and vermicompost was an important organic material that might be an alternative to farmyard manure.

Nitrogen Gain and Loss Along an Ecosystem Sequence: From Semi-desert to Rainforest

Plants and microorganisms, besides the climate, drive nitrogen (N) cycling in ecosystems. Our objective was to investigate N losses and N acquisition strategies along a unique ecosystem-sequence (ecosequence) ranging from arid shrubland through Mediterranean woodland to temperate rainforest. These ecosystems differ in mean annual precipitation, mean annual temperate, and vegetation cover, but developed on similar granitoid soil parent material, were addressed using a combination of molecular biology and soil biogeochemical tools. Soil N and carbon (C) contents, δ15N signatures, activities of N acquiring extracellular enzymes as well as the abundance of soil bacteria and fungi, and diazotrophs in bulk topsoil and rhizosphere were determined. Relative fungal abundance in the rhizosphere was higher under woodland and forest than under shrubland. This indicates toward plants' higher C investment into fungi in the Mediterranean and temperate rainforest sites than in the arid site. Fungi are likely to decompose lignified forest litter for efficient recycling of litter-derived N and further nutrients. Rhizosphere—a hotspot for the N fixation—was enriched in diazotrophs (factor 8 to 16 in comparison to bulk topsoil) emphasizing the general importance of root/microbe association in N cycle. These results show that the temperate rainforest is an N acquiring ecosystem, whereas N in the arid shrubland is strongly recycled. Simultaneously, the strongest 15N enrichment with decreasing N content with depth was detected in the Mediterranean woodland, indicating that N mineralization and loss is highest (and likely the fastest) in the woodland across the continental transect. Higher relative aminopeptidase activities in the woodland than in the forest enabled a fast N mineralization. Relative aminopeptidase activities were highest in the arid shrubland. The highest absolute chitinase activities were observed in the forest. This likely demonstrates that (a) plants and microorganisms in the arid shrubland invest largely into mobilization and reutilization of organically bound N by exoenzymes, and (b) that the ecosystem N nutrition shifts from a peptide-based N in the arid shrubland to a peptide- and chitin-based N nutrition in the temperate rainforest, where the high N demand is complemented by intensive N fixation in the rhizosphere.

Potential of Phototrophic Purple Nonsulfur Bacteria to Fix Nitrogen in Rice Fields.

Biological nitrogen fixation catalyzed by Mo-nitrogenase of symbiotic diazotrophs has attracted interest because its potential to supply plant-available nitrogen offers an alternative way of using chemical fertilizers for sustainable agriculture. Phototrophic purple nonsulfur bacteria (PNSB) diazotrophically grow under light anaerobic conditions and can be isolated from photic and microaerobic zones of rice fields. Therefore, PNSB as asymbiotic diazotrophs contribute to nitrogen fixation in rice fields. An attempt to measure nitrogen in the oxidized surface layer of paddy soil estimates that approximately 6–8 kg N/ha/year might be accumulated by phototrophic microorganisms. Species of PNSB possess one of or both alternative nitrogenases, V-nitrogenase and Fe-nitrogenase, which are found in asymbiotic diazotrophs, in addition to Mo-nitrogenase. The regulatory networks control nitrogenase activity in response to ammonium, molecular oxygen, and light irradiation. Laboratory and field studies have revealed effectiveness of PNSB inoculation to rice cultures on increases of nitrogen gain, plant growth, and/or grain yield. In this review, properties of the nitrogenase isozymes and regulation of nitrogenase activities in PNSB are described, and research challenges and potential of PNSB inoculation to rice cultures are discussed from a viewpoint of their applications as nitrogen biofertilizer.

Nitrogen retention, nutrient digestibility and growth efficiency of Nile tilapia ( Oreochromis niloticus ) fed dietary lysine and reared in fertilized ponds

Two diets were formulated, a low lysine (LowL) and a balanced lysine diet (BalL), containing 9.10 and 13.10 g lysine kg−1 feed, respectively. Twenty fish (30.2 ± 1.9 g) per tank were stocked in 110-L tanks, mounted in a recycling aquaculture system (RAS), and nine hundred fish (17.2 ± 1.6 g) per pond were stocked in 200 m2 fertilized ponds (FPS). Four replicates in RAS and five replicates in FPS were assigned for each diet tested. Fish were fed with the experimental diets at a feeding rate based on metabolic body weight, twice daily for 70 days. Fish fed the BalL diet in RAS had a higher yield (kg m−3), specific growth rate, nitrogen retention efficiency (%), protein efficiency ratio (g g−1 protein), protein content and essential amino acid content, as well as a better feed conversion ratio (p < .05). Lysine levels did not significantly affect fish survival (%), feed intake and apparent digestibility coefficients of nutrients. In contrast, in FPS, dietary lysine content did not (p > .05) affect the growth indices of nutrient utilization, survival (%), body composition and essential amino acids or nitrogen utilization efficiency. Percentage compositions of plankton in the gut contents and plankton abundances in water were approximately the same between diets. The Pearson correlation coefficient (r) between plankton abundance and growth in fish fed the LowL diet was .761 and −.961 for phytoplankton and zooplankton, respectively, compared with .50 and .54 in fish fed the BalL diet. The contribution of the natural food to nitrogen gain was 30% in fish fed the LowL diet, compared with 21% in fish fed the BalL diet (p < .05). The present study shows that natural food compensated for the deficiency of dietary lysine and improved the protein efficiency ratio by 46%, when compared to Nile tilapia grown in clear-water tanks.

Effect of feeding frequency on performance, nutrient digestibility, energy and nitrogen balances in juvenile African catfish (Clarias gariepinus) fed diets with two levels of crystalline methionine

In this study, the effect of feeding frequency and its interaction with crystalline methionine supplementation level on performance, digestion, energy and nitrogen balances was assessed. The experiment had a 2 × 4 factorial design, testing two levels of crystalline methionine (Met) and four feeding frequencies. The two diets contained Met either just fulfilling or exceeding the Met requirement of African catfish (Clarias gariepinus). African catfish with initial mean weight of 44 g were allocated to one of four feeding frequencies (six, two, one time (s) per day and two times out of three days) in a recirculation aquaculture system. Fish were fed an equal daily ration for 32 days. Performance parameters, nutrient digestibility, body composition, and nutrient balances were evaluated. Except for digestible nitrogen intake and dry matter body content, none of tested parameters was affected by the interaction between dietary Met levels and feeding frequencies. Growth, energy and nitrogen gain were unaffected by feeding frequency as well as dietary Met level. FCR was low, being 0.84 averaged over all treatments. However, feeding frequency affected feed intake and the apparent digestibility coefficient (ADC) of nutrients. Feeding at lowest frequency was accompanied by a lower feed consumption compared to other frequencies (P < 0.001). At higher frequency, ADC was higher for macronutrients but lower for phosphorus and magnesium. It was concluded that the asynchronous availability of AA for protein synthesis, which is often suggested to cause a sub-optimal utilization of crystalline AA, was not influenced by feeding frequency. However, feeding at a low frequency hampered daily feed intake of African catfish. Whereas, higher frequency improved nutrient digestibility, though it did not result in improved growth probably due to the higher energy required for maintenance related to physical activities at higher frequency.

Potential of Melia dubia agroforestry system in soil improvement and environmental sustainability

The current study intended to understand the influence of Melia dubia based agroforestry system on soil properties. The research was carried out at Gillan Khera in district Fatehabad, situated in the semi-arid region of Haryana. Analysis of soil samples were done for pH, electrical conductivity (EC), organic carbon, soil moisture and available nitrogen, phosphorus and potassium. The soil pH and EC decreased more under trees than under control (sole wheat crop) i.e, 8.09 to 7.89 and 0.46 to 0.44 dSm-1 respectively. However, the amount of N, P, K, organic carbon (131.38, 16.00, 301.10 (kg/ha) and 0.46 % respectively) and soil moisture content was found higher in intercropped conditions at both soil depths. Extra moisture in shaded conditions resulting in the breakdown of litter, mineralization and nitrogen gain at a faster rate compared to full sunlight conditions justifies the increased amount of nutrients, organic carbon and other favorable changes in the soil under trees. The current study recommends Melia dubia based agroforestry system as an excellent opportunity in order to enhance soil fertility and for environmental sustainability.

Dietary arginine requirement in diets of GIFT strain of Nile tilapia, Oreochromis niloticus : Effects on growth performance, whole‐body composition, growth‐related gene expression and haemato‐biochemical responses

This study aims to evaluate the effects of dietary arginine supplementation on growth performances, whole-body composition, haemato-biochemical responses and growth-related gene expression in juvenile GIFT tilapia. Five corn-soy-based isonitrogenous (322 g/kg) and isoenergetic (17.4 MJ/kg) diets were formulated to contain graded levels of dietary arginine (14.7, 15.5, 16.4, 17.6 and 18.5 g/kg of diet). Each diet was randomly assigned to triplicate groups of 30 fish (4.4 ± 0.2 g) per experimental unit, which were fed thrice a day (09:00, 13:00 and 17:00 h) for 60 days. Growth performances and feed utilization were improved in fish fed arginine at 16.4 g/kg of diet compared with other dietary treatments. No significant differences were observed in the whole-body proximate composition, amino acid profile and haematological responses of fish fed graded levels of dietary arginine. However, significant interactions were observed in the blood biochemical responses and mRNA expression of MyoD, Myogenin, GH, IGF-1, GHR-1 and Pax7 in fish fed diets with graded levels of arginine, while dietary arginine levels had no effect on the mRNA expression of myostatin and IGF-2. Second-order polynomial regression analysis of weight gain and nitrogen gain against dietary arginine levels indicated that the optimum dietary arginine requirement for maximum growth and feed utilization of juvenile GIFT tilapia was estimated to be 16.7–16.8 g/kg of diet or 51.8–52.2 g/kg of protein.

Оценка взаимодействия видов многолетних мятликовых трав (Poaceae) с клевером ползучим (Trifolium repens L.) в смешанных агрофитоценозах в контексте биологизации семеноводства

Nitrogen consumption is one of the most important factors and necessary conditions for plant growth and development. The contribution from the biological fixation of N2 by legumes in grass mixtures can reduce or completely replace the need for industrial nitrogen fertilizers for perennial bluegrass grasses. When white clover is cultivated in grass mixtures, the net nitrogen gain to the ecosystem from the atmosphere during the growing season as a result of biological fixation can vary from 100 to 300 kg/ha or more. This is equivalent in effect to the application of mineral nitrogen fertilizers on grass in doses from 150 to 350 kg/ha. Types and varieties of perennial grasses have different competitiveness and complementarity when they are jointly cultivated in mixed crops. The use of grasses to create less lying grass stands allows you to increase the collection of white clover seeds. When cultivating white clover in grass mixtures, there was a decrease in the biological yield of seeds compared to mono-crop by 15–38% due to a decrease in the number of generative shoots. However, seed losses during harvesting decreased by up to 9–23% depending on the type of accompanying cereal crop and the method of harvesting. They were minimal in mixed crops of clover with pasture ryegrass or reed fescue and accounted for 9–11% and 12–13% of the biological yield of seeds, respectively. The highest seed collections were obtained from grass stands of the second year of use without the use of nitrogen fertilizers from crops of pasture ryegrass, reed fescue and meadow fescue: 761, 402 and 373 kg/ha, respectively. Along with the types of cereal components, the nature of plant interaction in grass mixtures and their response to anthropogenic stresses also depend on the genotypes of white clover varieties. A comparative assessment of the effectiveness of cultivating clover varieties mixed with reed fescue showed that the highest collection of legume seeds 188 kg/ha from grass stands of the first year of use was provided by the 'Lugovik' variety – 36–68% more than with grass mixtures of the cv. 'Volat' variety f. giganteum and cv. 'VIK 70' of the f. hollandicum variety.

Urea-molasses Pre-treatment to Enhance Nitrogen Gain, Digestibility, Intake and Milk Yield from Crop-Residues in Smallholder Dairy Farms in Eastern Africa

Urea-molasses Pre-treatment to Enhance Nitrogen Gain, Digestibility, Intake and Milk Yield from Crop-Residues in Smallholder Dairy Farms in Eastern Africa

Estimation of nitrogen fixation in nutrient management options under soybean-wheat cropping sequence in an ustochrepts soil

Soybean- wheat is the dominant cropping system grown on Madhya Pradesh due to congenial climate, development of agro industries and export opportunities. Both are high value crops and raising them using organics may further improve product quality and help in sustaining system productivity on long term basis. A study on impact assessment of nutrient management options and estimation of nitrogen fixation by soybean under different nutrient management options was studied on soybean wheat system. For estimation of nitrogen fixation annual input output N balance technique was used. The experiment was initiated in Kharif 2015 comprising the nine treatments, viz control (no fertilizer and no manure), 100% RDF, 50% RDF + 50% FYM, 50% RDF + 50% VC, 100% FYM, 100% VC, 100% RDF + 25 kg ZnSO4 (First year), 100% RDF (DAP as a source of P) and 100% RDF + 0.5 kg Ammonium molybdate in both the crops with three replication arranged in a randomized block design. The estimated amount of nitrogen fixed by soybean annually varied from 54.91 to 67.46 kg/ha, however net gain of nitrogen in soil after offsetting the nitrogen derived by soybean ranged from 26.11 kg ha-1 in control to 9.47 kg ha-1 in 100% RDF + Zn, 8.99 kg ha-1 in 100% RDF + 0.5 kg AM, 4.94 kg ha-1 in 100% RDF, 4.52 kg ha-1 in 50% RDF + 50% Vermi-compost annually depending upon the mode of nutrient supply kg/ha, annually. Maximum nitrogen gain was recorded 67.46 kg ha-1 on 100% RDF + Zn nutrient option. There was a linear relationship between the amount of harvestable biomass nitrogen and residual biomass nitrogen. The highest percentage of nitrogen derived from atmosphere(%Ndfa) was recorded in the control treatment, but the highest amount of nitrogen (104.8 kg ha-1) fixed was found in the 50% RDF+50% Vermi Compost nutrient option. Conjunctive use of organic and inorganic source of nutrient is the best option to harness the nitrogen fixation potential of soybean.

Effect of dietary carbohydrate to lipid ratio on performance of Nile tilapia and enhancement of natural food in pond aquaculture

This study tested the effect of two diets differing in carbohydrate to lipid (CHO:LIP) ratio (4.7 vs. 19.5 g/g) on the contribution of natural food and the total fish production in tilapia ponds. Eight ponds, each divided into three equally sized compartments, were assigned to one of the two diets, which differed in CHO:LIP ratio but had the same digestible protein to digestible energy (DP:DE) ratio (15.5 and 15.6 g/MJ). Ponds were fed equal amounts of crude protein. Three feeding levels (no, low and high) were nested in each pond in a split plot design. Average body weight of fish at stocking was 90 g, and the duration of the experiment was 42 days. Increasing the CHO:LIP ratio had no impact on tilapia production. However, the feeding level influenced both biomass gain, specific growth rate and survival. The apparent digestibility coefficient (ADC) for fat and carbohydrate was influenced by dietary CHO:LIP ratio but ADC for energy was unaffected. Proximate analysis of fish body composition showed no effect of diet except for levels of ash. Diet had no effect on the organic matter composition of the faeces, and the contribution of natural food to fish nitrogen gain. Therefore, we postulate that changing the dietary non-protein energy source from lipid to carbohydrate does not have any impact on tilapia culture in semi-intensive ponds.

Effect of integrated nutrient management on sweet corn&#8211;potato cropping system: Productivity, economic yield and soil nutrient balance

The study was conducted to estimate the productivity, economic yield and soil nutrient balance of integrated nutrient management in sweet corn-potato cropping sequence was conducted during kharif and rabi season of 2014-15 to 2015-16 at Instructional Research Farm, Central Campus, Post Graduate Institute, Mahatma Phule Krishi Vidyapeeth, Rahuri. The performance of sweet corn–potato cropping sequence was assessed in terms of residual fertility status at the end of two years crop sequence. The treatment T1-100% GRDF to preceding crop sweet corn during kharif season registered maximum net gain of nitrogen, phosphorus and potassium (+49.19, +6.54 and +80.74 kg ha-1) at the end of two years experimentation.

Dietary nitrogen utilisation and prediction of amino acid requirements in equids

The equine population represents an important sector of animal agriculture and, thus, contributes to environmental contamination. The horse industry lags behind other livestock industries in developing prediction models to estimate N and amino acid (AA) requirements aimed at precision feeding and management to optimise animal health and performance while mitigating nutrient excretion. Effective predictions of N utilisation and excretion are based on knowledge of ingredient protein quality and the determinants of N and AA requirements. Protein quality is evaluated on the basis of N and AA digestibility and AA composition. Amino acid composition of grains, pulses and oil seeds is extensive, but there is large deficit on that of forages. Several studies have reported on pre- and post-caecal N digestibility in horses, demonstrating that a large proportion of N from forages is metabolised post-caecally. Few have reported on AA digestibility. It is proposed that whole-tract (i.e. faecal) N and AA digestibility be used in evaluating feed-ingredient protein quality in equids to begin designing predictive models of N and AA requirements. Nitrogen gain and AA composition in deposited tissues and their corresponding efficiency of utilisation are the key determinants for a prediction model. We estimated that N utilisation for maintenance is 0.74. Maintenance requirements for N and AA were derived from faecal N and AA losses in horses and expressed as a function of dry-matter intake and from integument losses in swine. Relative to our factorial model, the NRC (2007) requirement for lysine and N is overestimated when based on a segmented curve and a breakpoint. When based on N equilibrium, lysine NRC (2007) requirement estimate agrees with our factorial model estimate, while N requirement is underestimated. The pool of AA profile used to express requirements of other essential AA has a large impact on requirement, as shown, in particular, for threonine. Threonine requirement based on faecal endogenous AA profile is higher than is lysine requirement for maintenance and lactation.