Influence of the Nitrate-N to Ammonium-N Ratio on Relative Growth Rate and Crude Protein Content in the Duckweeds Lemna minor and Wolffiella hyalina

In order to produce protein-rich duckweed for human and animal consumption, a stable cultivation process, including an optimal nutrient supply for each species, must be implemented. Modified nutrient media, based on the N-medium for duckweed cultivation, were tested on the relative growth rate (RGR) and crude protein content (CPC) of Lemna minor and Wolffiella hyalina, as well as the decrease of nitrate-N and ammonium-N in the media. Five different nitrate-N to ammonium-N molar ratios were diluted to 10% and 50% of the original N-medium concentration. The media mainly consisted of agricultural fertilizers. A ratio of 75% nitrate-N and 25% ammonium-N, with a dilution of 50%, yielded the best results for both species. Based on the dry weight (DW), L. minor achieved a RGR of 0.23 ± 0.009 d−1 and a CPC of 37.8 ± 0.42%, while W. hyalina’s maximum RGR was 0.22 ± 0.017 d−1, with a CPC of 43.9 ± 0.34%. The relative protein yield per week and m2 was highest at this ratio and dilution, as well as the ammonium-N decrease in the corresponding medium. These results could be implemented in duckweed research and applications if a high protein content or protein yield is the aim.

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Compensatory growth of Malaysian prawns reared at high densities during the nursery phase

Revista Brasileira de Zootecnia ◽

10.1590/s1516-35982011000400001 ◽

2011 ◽

Vol 40 (4) ◽

pp. 701-707 ◽

Cited By ~ 9

Author(s):

H.L.A. Marques ◽

J.V. Lombardi

Keyword(s):

Growth Rate ◽

Relative Growth Rate ◽

Conversion Efficiency ◽

Crude Protein ◽

Compensatory Growth ◽

Macrobrachium Rosenbergii ◽

Average Weight ◽

Feed Conversion ◽

Relative Growth ◽

Feed Conversion Efficiency

The objective of this work was to verify the occurrence of compensatory growth in Malaysian prawn (Macrobrachium rosenbergii) reared in pens, after being stocked in cages under high densities during nursery phase. The experiment was carried out in 0.5 m² cages and 2-m² pens set in natural bottom pond with 2,400 m². Prawn post-larvae (PL) with an average weight of 0.026 ± 0.012 g (nursery phase) were initially stocked in 16 cages at the densities of 50, 400, 800 and 1,200 PL m-2. Sixty days later, prawns were transferred to 16 growing pens, at the density of 12 prawns m-2. Initial average weight of the prawn in this phase was the final average weight registered in the nursery phase, as follows: 50 PL m-2 = 2.3 ± 0.3 g; 400 PL m-2 = 0.5 ± 0.03 g; 800 PL m-2 = 0.3 ± 0.05 g and 1,200 PL m-2 = 0.1 ± 0.01 g. Commercial rations for prawns (35% crude protein) were given once a day, in the afternoon. After 244 days, survival, average weight and biomass did not differ significantly among prawns with different initial average weight. Relative growth rate was significantly greater in prawns previously stocked at 1,200 PL m-2 and feed conversion efficiency was significantly better for those previously stocked at 400 and 1,200 PL m-2. These results suggest the existence of partial compensatory growth in M. rosenbergii, what can successfully carry on stocking of prawns of this species at high densities in the nursery phase.

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A note on the implantation of intensively-fed beef cattle with hexoestrol

Animal Science ◽

10.1017/s0003356100027069 ◽

1969 ◽

Vol 11 (3) ◽

pp. 419-422 ◽

Cited By ~ 6

Author(s):

A. Macdearmid ◽

T. R. Preston

Keyword(s):

Growth Rate ◽

Beef Cattle ◽

Protein Content ◽

Conversion Efficiency ◽

Crude Protein ◽

Fat Content ◽

Crude Protein Content ◽

Feed Conversion ◽

Feed Conversion Efficiency ◽

Single Implant

SUMMARYIn the first of two experiments, steers which received a single implant of 60 mg hexoestrol grew 24% faster than non-implanted controls and 7% faster than steers given 30 mg. The growth rate of the steers given a single implant of 60 mg did not differ significantly from that of animals implanted twice with 30 mg or 5 times with 15 mg. In the second experiment, steers given 60 mg grew 23% faster than controls and their feed conversion efficiency was 13% better; the hexoestrol treatment resulted in a saving of 131 kg feed per animal. The tenth-rib joints of steers given 60 mg had a higher crude-protein content and lower fat content than those from non-implanted animals.

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Does the direct effect of atmospheric CO2 concentration on leaf respiration vary with temperature? Responses in two species of Plantago that differ in relative growth rate

Physiologia Plantarum ◽

10.1034/j.1399-3054.2001.1140109.x ◽

2002 ◽

Vol 114 (1) ◽

pp. 57-64 ◽

Cited By ~ 37

Author(s):

Dan Bruhn ◽

Teis N. Mikkelsen ◽

Owen K. Atkin

Keyword(s):

Growth Rate ◽

Relative Growth Rate ◽

Direct Effect ◽

Co2 Concentration ◽

Atmospheric Co2 ◽

Leaf Respiration ◽

Relative Growth ◽

Atmospheric Co2 Concentration ◽

Temperature Responses

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Food products. Determination of the total nitrogen content by combustion according to the Dumas principle and calculation of the crude protein content

10.3403/30109615u ◽

2015 ◽

Keyword(s):

Nitrogen Content ◽

Protein Content ◽

Total Nitrogen ◽

Crude Protein ◽

Food Products ◽

Total Nitrogen Content ◽

Crude Protein Content

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Cereals and pulses. Determination of the nitrogen content and calculation of the crude protein content. Kjeldahl method

10.3403/30131418 ◽

2006 ◽

Keyword(s):

Nitrogen Content ◽

Protein Content ◽

Crude Protein ◽

Crude Protein Content ◽

Kjeldahl Method

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Animal feeding stuffs. Determination of nitrogen content and calculation of crude protein content

10.3403/30198882 ◽

2009 ◽

Keyword(s):

Nitrogen Content ◽

Protein Content ◽

Crude Protein ◽

Crude Protein Content ◽

Animal Feeding

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Early productivity and crude protein content of establishing forage swards composed of combinations of native grass and legume species in mixed-grassland ecoregions

Canadian Journal of Plant Science ◽

10.4141/cjps2012-261 ◽

2013 ◽

Vol 93 (3) ◽

pp. 445-454 ◽

Cited By ~ 10

Author(s):

Jenalee M. Mischkolz ◽

Michael P. Schellenberg ◽

Eric G. Lamb

Keyword(s):

Protein Content ◽

Crude Protein ◽

Plant Density ◽

Warm Season ◽

Forage Yield ◽

Schizachyrium Scoparium ◽

Legume Species ◽

Crude Protein Content ◽

Native Grass ◽

Western Wheatgrass

Mischkolz, J. M., Schellenberg, M. P. and Lamb, E. G. 2013. Early productivity and crude protein content of establishing forage swards composed of combinations of native grass and legume species in mixed-grassland ecoregions. Can. J. Plant Sci. 93: 445–454. We evaluated the early establishment productivity of forage swards of native, perennial, cool and warm season grasses, and legumes as they have the potential to provide non-invasive, productive, and drought resistant rangelands. Seven species with agronomic potential and a broad native geographic distribution were selected for testing including: nodding brome [Bromus anomalus (Coult.)], blue bunch wheatgrass [Pseudoregneria spicata (Pursh)], western wheatgrass [Pascopyrum smithii (Rydb.)], side oats grama [Bouteloua curtipendula (Michx.)], little blue stem [Schizachyrium scoparium (Michx.)], purple prairie clover [Dalea purpurea (Vent.)], and white prairie clover [Dalea candida (Willd.)]. Forage swards, including all seven monocultures, 21 two-species mixtures and a mixture with all species, were planted in two sites, Saskatoon and Swift Current, Saskatchewan. Western wheatgrass (WWG) had the highest overall plant density and the strongest effect on the forage yield of the forage swards; however, productivity and crude protein content were not reduced when other species were also included in the forage sward. Dalea spp. did not establish as well as the other species, but had the highest crude protein concentrations. This work provides insight into forage sward development at the establishment stage; additional work is required to determine long-term species impacts for well established forage swards.

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