Mostafa Akbari Alaei; Javad Rezaei; Yousef Rouzbehan
Volume 25, Issue 4 , December 2023, , Pages 357-373
Abstract
This research was conducted to compare the effect of different zinc sources on in vitro microbial populations, hydrolytic enzymes and ruminal fermentation products in sheep. Five diets without zinc supplement (control) or containing ZnSO4, ZnO, nano-ZnO and Zn-methionine were assessed. The 24 and 72-h ...
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This research was conducted to compare the effect of different zinc sources on in vitro microbial populations, hydrolytic enzymes and ruminal fermentation products in sheep. Five diets without zinc supplement (control) or containing ZnSO4, ZnO, nano-ZnO and Zn-methionine were assessed. The 24 and 72-h gas tests were conducted in a completely randomized design where the microbial populations, hydrolytic enzymes, methane, antioxidant activity, organic matter digestibility (OMD), metabolizable energy (ME), truly degraded substrate (TDS), microbial biomass, partitioning factor (PF) and volatile fatty acids (VFA) were determined. Total proteolytic bacteria count and protease activity decreased due to the usage of organic, inorganic and nano-particle sources of zinc (P<0.05). The use of methionine, oxide and sulfate sources of zinc increased alpha-amylase activity (P<0.05). Total protozoa number in the 24-h incubation tended to decrease owing to dietary zinc supplements. Total cellulolytic bacteria, carboxymethyl-cellulase, microcrystalline-cellulase, filter paper-degrading activity, antioxidant capacity, microbial biomass and PF were the same among treatments. Zinc methionine, oxide and sulfate supplements increased OMD, ME, TDS and total VFA, whereas decreased ammonia and acetate:propionate ratio (P<0.05). Also, 24-h methane production decreased with the use of zinc supplements (P<0.05). Overall, the dietary addition of sulfate, oxide and methionine- sources of zinc is recommended with the aim of improving alpha-amylase activity and digestibility and reducing proteolytic activity, ammonia accumulation and methane, but feeding nano-ZnO is not recommended. More research is needed on the effect of zinc sources on rumen microorganisms and enzymes in different dietary conditions.
Leila Taherabadi; Farokh Kafilzadeh
Volume 25, Issue 2 , July 2023, , Pages 169-181
Abstract
Introduction: Increased livestock production can be achieved through the cultivation of high-quality forages with high-yielding capacity. Napier grass has been introduced to all tropical and subtropical areas of the world and is used as a forage crop with high potential productivity in terms of annual ...
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Introduction: Increased livestock production can be achieved through the cultivation of high-quality forages with high-yielding capacity. Napier grass has been introduced to all tropical and subtropical areas of the world and is used as a forage crop with high potential productivity in terms of annual dry matter yield. However, both dry matter yield and nutritional quality of this grass have been affected by different cutting interval. This grass has been neither grown nor studied as a source of forage for ruminant nutrition in Iran.This research was conducted to identify the appropriate cutting interval for Napier grass to produce the maximum nutritive value and yield.
Material and methods: Napier grass was cultivated in a complete randomised block design with three replicates. During the growth season, the cutting intervals were 16-20, 24-28, 43 d or 136 d after planting to corresponding cutting heights of 50, 100, 150 and 300 cm. Hence, from each plot 6, 4, 2, or 1 cuts were harvested, respectively. Cell wall fractions, organic matter, and crude protein of Napier grass from different cuts were determined. Dry matter and organic matter digestibility and in-vitro ruminal fermentation kinetics of the forages were also determined. Biomass production of Napier grass under different cutting interval programs was also assessed.
Results and Discussion: The highest yield of dry matter of Napier grass (25.1 tons per hectare) was observed when only one cut was harvested at the end of vegetative stage (height of 300 cm). The digestibility of organic matter (OMD) ranged from 60 to 70 % in all treatments and the highest OMD was observed at the height of 50 cm. The maximum dry matter and digestible organic matter per hectare (15.9 and 14.2 tons, respectively) was produced when forage was harvested in one cut at the height of 300 cm. There was no difference in the yield of digestible dry matter and digestible organic matter of the forage harvested at the height of 50 and 100 cm. The concentration of crude protein in forages from different cuts ranged from 7.1 to 14.2 % and neutral detergent fiber ranged 65.7 to 76.2 %. The highest concentration of crude protein and the lowest cell wall components were observed at the height of 50 cm. The lowest and the highest gas production potential and fractional rate of gas production were observed at the cutting height of 300 cm and 50 cm, respectively.
Conclusion: The present study showed that it is possible to obtain higher quality of Napier grass by shortening the harvesting intervals. However, this resulted in a pronounce decrease in the yield of organic matter and digestible dry matter yield per hectare. The highest organic matter and digestible dry matter per hectare was produced when Napier grass was harvested only once (136 d after planting and height of 300 cm) at the end of vegetative stage.
Seyed Morteza Vaghar Seyedin; Mohsen Mojtahedi; Mohhamad Hasan Fathi Nasri; Seyed Ehsan Ghiasi
Volume 21, Issue 4 , January 2020, , Pages 487-497
Abstract
This study aimed to evaluate the buffering capacity of some buffer mixtures and the effect of their inclusion in the diet on in vitro ruminal fermentation parameters. For this purpose, five buffer mixtures were prepared as: 1) containing 15% sodium bicarbonate + 15% magnesium oxide + 35% magnesium ...
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This study aimed to evaluate the buffering capacity of some buffer mixtures and the effect of their inclusion in the diet on in vitro ruminal fermentation parameters. For this purpose, five buffer mixtures were prepared as: 1) containing 15% sodium bicarbonate + 15% magnesium oxide + 35% magnesium carbonate + 35% sodium bentonite; 2) containing 35% sodium bicarbonate + 35% magnesium oxide + 15% magnesium carbonate + 15% sodium bentonite; 3) containing 20% sodium bicarbonate + 40% magnesium oxide + 20% magnesium carbonate + 20% sodium bentonite; 4) containing 40% sodium bicarbonate + 20% magnesium oxide + 20% magnesium carbonate + 20% sodium bentonite; and 5) containing 16% sodium carbonate + 35% magnesium oxide +22% magnesium carbonate + 5% sodium bentonite and 22% monobasic potassium phosphate. Buffering capacity and buffer value index were measured. Then the effect of buffer mixtures on gas production potential, pH, ammonia nitrogen concentration and in vitro dry matter disappearance (IVDMD) was investigated. Bufferingcapacity and buffer value index of buffer mixture 2 was higher than other buffer compounds (P<0.05). Buffer mixture 4 increased gas production (P<0.05). IVDMD was the same between the buffer mixtures and only buffer mixture 4 and 1 were different (P<0.05). The use of buffer mixture 2 increased the pH of the batch culture (P<0.05). Overall, the results of this experiment showed that the use of buffer mixture2 could have an effective role in preventing pH drop and consequently reducing acidosis.