Uticaj fenofaze razvića na zastupljenost lignina i hranljivu vrednost lucerke i crvene deteline

Abstract

Ispitivan je uticaj sorte, faze razvića i otkosa na hranljivu vrednost lucerke (Medicago sativa L.) i crvene deteline (Trifolium pratense L.). Hemijski sastav je odreñen prema Weende i Detergent sistemu analize. Primenom CNCPS sistema analize utvrñena je priroda proteina i ugljenih hidrata ispitivanih biljnih vrsta, odnosno oblik u kome su ove hranljive supstance zastupljene, a koji jeste najznačajniji činilac koji odreñuje stepen i brzinu razlaganja u buragu. U ovim istraživanjima utvrñene su razlike u sadržaju lignina ispitivanih krmnih vrsta u zavisnosti od starosti biljaka, kao i uticaj lignifikacije ćelijskih zidova na svarljivost ovih hraniva. Prinos suve materije lucerke i crvene deteline zavisio je od sva tri ispitivana faktora i njihovih interakcija. Domaća sorta lucerke je produktivnija (6,8 do 2,3 t ha-1 od prvog do četvrtog otkosa, odnosno od 3,4 do 5,5 t ha-1 od prve do treće faze razvića) u odnosu na američku (5,9 do 2,2 t ha-1 od prvog do četvrtog otkosa, odnosno od 2,7 do 5,2 t ha-1 od prve do treće faze razvića). Američka populacija lucerke je sadržala veću količinu sirovih proteina (197,9 g kg-1 SM) u odnosu na domaću sortu (188,7 g kg-1 SM), dok je tetraploidna sorta crvene deteline sadržala veću količinu sirovih proteina (181,3 g kg-1 SM) u odnosu na diploidnu sortu (174,5 g kg-1 SM). Najveći sadržaj sirove celuloze je konstatovan u drugom otkosu sorte K 28 (407,6 g kg-1 SM). Faza razvića je značajno uticala na udeo lignina u suvoj materiji lucerke, čija se količina povećala od prvog do trećeg otkosa. U suvoj materiji crvene deteline je konstatovana značajno manja količina lignina. Najveća svarljivost suve materije je ustanovljena u četvrtom otkosu lucerke (754,4 g kg-1 SM), odnosno u trećem otkosu crvene deteline (820,1 g kg-1 SM), a najmanja u drugom otkosu, što se može objasniti najvećim učešćem strukturnih ugljenih hidrata u ovom otkosu...

The effect of cultivar, stage of development and the cuts on the nutritional value of alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.) was investigated. The chemical composition was determined according to Weende and Detergent system of analysis. Applying CNCPS system of analysis the nature of protein and carbohydrates of plant species were examined, and a form of these nutrients were present in the plants, which is the most important factor determining the rate of degradation in the rumen. In this investigation, differences in lignin content of investigated forage crops were determined depending on the plant development, and the influence of lignifications on the cell wall digestibility of these forages. Dry matter yield of alfalfa and red clover depended on all three factors and their interactions. The local variety of alfalfa, K 28, was more productive (from 6,8 to 2,3 t ha-1 from first to fourth cut, and from 3,4 to 5,5 t ha-1 from first to third stage of development) compared to US variety, G+13R+CZ (from 5,9 to 2,2 t ha-1 from first to fourth cut, and from 2,7 to 5,2 t ha-1 from first to third stage of development). US alfalfa population contained a larger amount of crude protein (197,9 g kg-1 DM) in relation to K 28 (188,7 g kg-1 DM), while the tetraploid cultivar of red clover contained a larger amount of crude protein (181,3 g kg-1 DM) in the relation to the diploid cultivar (174,5 g kg-1 DM). The highest content of crude fiber was noted in the third stage of development in the second cut of alfalfa, K 28 cultivar (407,6 g kg-1 DM). Stage of development had a significant impact on the proportion of lignin in the dry matter of alfalfa and the amount of lignin increased from the first to the third cut. Significantly lower amount of lignin was detected in the dry matter of red clover. The highest dry matter digestibility was detected in the fourth cut of alfalfa (754,4 g kg-1 DM), and the third cut of red clover (820,1 g kg-1 DM), and lowest digestibility was determined in the second cut, which could be explained by a higher amount of structural carbohydrates in this cut...