Rumen In Vitro Fermentation and In Situ Degradation Kinetics of Winter Forage Brassicas Crops

Abstract

Simple SummaryWinter brassica crops such as kales and swedes are used to supply feed in times of seasonal shortage. However, to the best of our knowledge, there is little information about the fermentation characteristics of these forages in the rumen. This study assessed the nutrient concentration, in vitro fermentation and in situ rumen degradation characteristics of Brassica oleracea (L.) ssp. acephala (kales) and Brassica napus (L.) ssp. napobrassica (swedes). The kales and swedes both showed different nutrient concentrations and fermented fast and extensively in the rumen. However, in vitro fermentation of swedes resulted in lower acetate and greater proportions of butyrate and propionate. Varieties of swedes showed more differences in terms of degradation and fermentation in the rumen compared to kale varieties.AbstractThe aim of the present study was to evaluate the nutritional value, the rumen in vitro fermentation, and the in situ degradation of Brassica oleracea (L.) ssp. acephala (kales) and Brassica napus (L.) ssp. napobrassica (swedes) for winter use. Five varieties of each brassica were used in three field replicates and were randomized in a complete block nested design. All forage varieties were harvested at 210 days post-sowing to analyze the chemical composition, in vitro gas production, volatile fatty acid (VFA) production and in situ dry matter (DM) and crude protein (CP) degradability. Kales presented higher DM and neutral detergent fiber (NDF) content (p < 0.01), whereas swedes showed higher CP, metabolizable energy (ME), glucose, fructose, total sugars, NFC, and nonstructural carbohydrate (NSC) content (p < 0.01). The kale and swede varieties differed in their CP and sugar concentrations, whereas the kale varieties differed in their DM and raffinose content. The rates of gas production were higher for swedes than for kales (p < 0.01). No differences between the brassica species (p > 0.05) were observed in the total VFA production, whereas kales had a higher proportion of acetate and swedes had higher proportions of butyrate (p < 0.05). Only the swede varieties showed differences in VFA production (p < 0.05). The soluble fraction “a”, potential and effective in situ DM degradability were higher in swedes (p < 0.01), but kales presented greater DM and CP degradation rates. Differences were observed between brassica species in the chemical composition, degradation kinetics, and ruminal fermentation products, whereas differences among varieties within species were less frequent but need to be considered.

Chemical Composition, Fatty Acid Profile and Sensory Characteristics of Chanco-Style Cheese from Early Lactation Dairy Cows Fed Winter Brassica Crops

“…The NDF ranges from 16.5 to 19.6% in swedes and, 27.1 to 32.8% for kale; whereas soluble fiber (SF) ranges from 24 to 38% [ 7 ]. The soluble fiber is mainly composed of pectins (7–9%), galactans, and β-glucans, among others [ 4 , 8 , 9 ].…”

“…Recent research has shown that fermentation of swedes results in lower acetate and greater proportions of butyrate and propionate [ 9 ], whereas kale offered at the same amount as grass pasture to dry cows resulted in lower proportions of propionate and greater butyrate [ 13 ]. Regarding the lipid fraction, brassicas have high contents of FA with >20 carbons, which is in agreement with previous research on different brassica species [ 14 , 15 ].…”

Acceptability, Preferences, and Palatability of Diets Containing Summer and Winter Brassica Forage in Growing Pigs: A Pilot Study

“…Pigs can digest and utilize DF, due to the capacity of their hindgut to absorb microbial fermentation end-products from DF such as short chain fatty acids (SCFA), branched chain fatty acids, lactate, and amines [ 4 ]. Brassica forages are annual crops that have been used as a supplement to pastures in times of seasonal shortage [ 7 , 8 ] and when water resources are limited [ 9 ]. Summer brassicas include turnip ( Brassica rapa L. subsp.…”

“…acephala ) and swede ( B. napus L. subsp. napobrassica ) [ 8 ]. The chemical composition of brassicas varies due to the leaf/bulb-stem ratio [ 10 , 11 ].…”

“…The insoluble fiber (IF in terms of NDF) ranges from 16.5% to 19.6% in swedes, 18% to 24% for turnip and rape, and 27.1% to 32.8% for kale; whereas soluble fiber (SF) ranges from 24% to 38% [ 11 ]. The SF is mainly composed of pectins (7–9%), galactans and β-glucans, among others [ 7 , 8 , 12 , 13 ].…”