Productivity, utilization, and nutritive quality of dallisgrass (Paspalum dilatatum) as influenced by stocking density and rest period under continuous or rotational stocking

This research aimed to determine the stocking density that support the best growth and survival rate of carp cultivated in aquaponic systems, and to study the water quality of carp culture with different stocking densities in aquaponic systems. The study used 12 aquaria measuring 40x40x40 cm each (water volume of 50 liters). The experimental fish are carp (Cyprinus carpio) weighing in average of 3.5 g/individual. The fish were cultivated with different stocking densities as treatment, including A = 4; B = 7; C = 10 and D = 13 individuals/aquarium. The fish were fed with pellet at 5%/body weight/day with a feeding frequency of two times a day. The study was conducted for 4 weeks. Data consisting of daily growth, survival and water quality parameters (temperature, pH, dissolved oxygen, ammonia, nitrite and nitrate) were measured once a week. The data obtained were analyzed by ANOVA. The results of the study showed that the difference in stocking density had no significant effect on the growth and survival of carp. Water quality was in a reasonable range to support the growth and survival of carp cultivated with aquaponic systems.Keywords: cultivation, carp, aquaponics, stocking density, growth

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Influence of soluble content losses on the ability of aerobic fungi to improve the nutritional content of pre-treated forages

Nigerian Journal of Animal Production ◽

10.51791/njap.v47i3.168 ◽

2020 ◽

Vol 47 (3) ◽

pp. 298-308

Author(s):

K. R. Idowu ◽

A. S. Chaudhry ◽

J. Dolfing ◽

V. O. A. Ojo

Keyword(s):

Secondary Metabolites ◽

Growth Conditions ◽

Water Soluble ◽

Optimal Conditions ◽

Similar Reduction ◽

Filtering Method ◽

Nutritive Quality ◽

Andropogon Gayanus ◽

The Impact

Fungal improvement of the nutritive content of low-quality forages can be affected by several factors among which loss of water-soluble content (WSC) plays a major role. To achieve this aim, two growth conditions i.e. forage-liquid ratios (1:3 and 1:5) and two inoculation times (14 and 28 days) were used to cultivate the selected fungi i.e. Pleurotus ostreatus (PO) at 30°C and Ceriporiopsis rivulosus (CR) at 20°C on Brachiaria decumbens (BD), Andropogon gayanus (AG), Triticum aestivum (TA) straw, Lolium perenne (LP), respectively with the view of selecting the optimal conditions that facilitate the release of WSC. The impact that losses of WSC have on the ability of fungi to improve the nutritive content (i.e. proximate, fibre, secondary metabolites and total antioxidant content) of the forages were then measured using 2 filtering methods i.e. light pump filtering method (LFM) and free flow filtering method (FFM). The optimal conditions that supported increased th soluble was identified as 28th day for both fungi; forage-liquid ratio of 1:5 for both fungi in most of the forages except BD (CR) and BD & AG (PO). The LFM led to lesser or no improvement in the nutritive quality of the upgraded forages while the opposite was recorded with the LFM. The LFM as against the FFM produced upgraded forages with lesser reduction in NDF; similar or higher ADF and lignin contents; and similar reduction in secondary metabolites and TAC when compared with un-improved forages. It can be concluded that the fungal improvement of the nutritive content of low-quality forages was negatively affected by the loss of WSC. It is therefore recommended that fungal improvement of the nutritive quality of low quality forages should be carried out with methods or techniques that facilitates little or no WSC loss in the upgraded forages.

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