RUMINANT NUTRITION SYMPOSIUM: The utility of lipid extracted algae as a protein source in forage or starch-based ruminant diets1,2

Abstract

Two experiments were conducted to determine the influence of lipid extracted algae (LEA) on OM digestibility, N flow, and rumen fermentation. Six samples of LEA were evaluated representing 2 genus of microalgae (Nannochloropsis spp. [n = 3] or Chlorella spp. [n = 3]). Four dual-flow continuous flow fermenters (2,700 mL) were used in a Latin square design to evaluate LEA in forage or concentrate diets compared with soybean meal. Temperature (39 °C), pH, solid (5%/h) and liquid (10%/h) dilution rates, and feed schedule were maintained constant for all experiments. Each experimental period consisted of 6-d adaptation and 4-d sampling periods. There were 7 treatments consisting of 6 different samples of LEA and a soybean meal control (SOY). Diets for Exp.1 were formulated to be 13.0% CP (DM basis) using either soybean meal or LEA and met or exceeded the requirements of a nonpregnant and nonlactating beef cow (450 kg). The forage portion consisted of sorghum-sudan hay (6.4% CP and 46.2% TDN, DM basis) and alfalfa (26.1% CP and 82.3% TDN, DM basis). Concentrate diets used in Exp. 2 met or exceeded the nutrient requirements of a (400 kg) growing steer and contained 85% fine ground corn and included 7% (DM basis) soybean meal or LEA. Data were analyzed as mixed model considering the effect of each LEA compared with soybean meal. Orthogonal contrasts were used to determine the overall effect of LEA genus vs. SOY. True OM digestibility were not influenced by LEA addition to forage diets (P ≥ 0.08) but increased with Chlorella LEA addition to concentrate diets (P < 0.01) but not Nannochloropsis LEA. Degradation of N was greater for SOY with forage diets and LEA for concentrate diets (P < 0.0001). Total VFA production was greatest for SOY in forage diets and increased when LEA was added to concentrate diets (P < 0.0001). Microbial efficiency did not differ between SOY and LEA in forage diets (P ≤ 0.08). In concentrate diets Nannochloropsis decreased microbial efficiency (P < 0.01). Microbial efficiency results for Chlorella were more variable for Nannochloropsis with 1 Chlorella spp. increasing microbial efficiency by 36% over SOY (P < 0.05) and the other Chlorella spp. decreasing microbial efficiency by approximately 42% compared with SOY (P < 0.01). Overall, the results from both experiments are promising for LEA as a protein feedstuff in ruminant diets. Further research is necessary to fully understand the interactions and consequences of upstream processes and what role algal strain plays in LEA quality.

The effect of dietary Chlorella vulgaris supplementation on micro‐organism community, enzyme activities and fatty acid profile in the rumen liquid of goats

“…Additionally, in a recent study, Lodge‐Ivey et al. () observed greater ammonia concentration in the rumen of cows fed a forage diet supplemented with lipid extracted C. vulgaris . It should be mentioned also here that in this study, the goats fed diets with relatively high forage‐to‐concentrate ratio.…”

“…Thus, it is clear that in vivo studies are required especially using microalgae with high protein content, such as Chlorella vulgaris, to determine their impact on methanogens population in the rumen. This assumption was further supported by the fact that recently C. vulgaris has been proposed as a protein source in cows diets (Lodge‐Ivey et al., ). Additionally, defatted biomass of microalgae species, derived from biofuel production, has been shown feasible in replacing corn and soybean meal in cattle diets (Lopex et al., ).…”

Variability of in vitro ruminal fermentation and nutritional value of cell‐disrupted and nondisrupted microalgae for ruminants

“…It is more likely that microbial yield was limited because of energy deficiency. Lodge‐Ivey, Tracey, and Salazar () investigated the effects of a complete replacement of soybean meal in forage or concentrate‐based diets by lipid‐extracted Chlorella or Nannochloropsis products in a continuous rumen fermentation system. Lipid‐extracted Nannochloropsis products consistently decreased microbial efficiency compared to soybean meal, while microbial efficiency was increased with some lipid‐extracted Chlorella products and decreased with others.…”

In vitro digestion of microalgal biomass from freshwater species isolated in Alberta, Canada for monogastric and ruminant animal feed applications

“…The WAB did not suppress methane emissions to any appreciable extent and LEB caused a substantial reduction, which was accompanied by reduced digestibility, but that was not much different from that caused by WAB. Lodge-Ivey et al [48] used continuous flow artificial rumen fermentation systems to assess the effect of complete replacement of soybean meal (7-15% of the diet) in forage and concentrate-based diets with Chlorella spp. LEB (3 products) and N. salina LEB (3 products) on IVD, rumen fermentation and N metabolism.…”