Spirulina (Spirulina platensis) algae supplementation increases microbial protein production and feed intake and decreases retention time of digesta in the rumen of cattle

Abstract

Cattle consuming pastures low in protein have low liveweight gain due to low rumen degradable protein (RDP) supply and thus low microbial crude protein (MCP) production and efficiency of MCP production [EMCP, g MCP/kg digestible organic matter (DOM)]. Nitrogen supplements can increase MCP production and EMCP of cattle grazing low protein pastures. The objective of this study was to compare the effects of supplementation with a non-protein-N source (NPN), in this case urea and ammonium sulfate (US), with a single-cell algal protein source (Spirulina platensis), on intake, microbial protein supply and digestibility in cattle. Nine cannulated Bos indicus steers [initial liveweight 250.1 ± 10.86 (s.d.) kg] were fed Mitchell grass hay (Astrebla spp; 6.1 g N, 746 g NDF/kg DM) ad libitum and were supplied with increasing amounts of US (0, 6, 13, 19 and 33 g US DM/kg hay DM) or Spirulina 0, 0.5, 1.4, 2.5 and 6.1 g Spirulina DM/kg W.day in an incomplete Latin square design. The response of MCP production and EMCP to increasing amounts of the two supplements was different, with a greater response to Spirulina evident. The MCP production was predicted to peak at 140 and 568 g MCP/day (0.64 and 2.02 g MCP/kg W.day) for the US and Spirulina supplements, respectively. The highest measured EMCP were 92 and 166 g MCP/kg DOM for the US and Spirulina treatments at 170 and 290 g RDP/kg DOM, respectively, or a Spirulina intake of 5.7 g DM/kg W.day. Increasing RDP intake from US and Spirulina resulted in an increase in Mitchell grass hay intake and rumen NH3-N concentration and reduced the retention time of liquid and particulate markers and digesta DM, NDF and lignin in the rumen with greater changes due to Spirulina. Total DM intake peaked at a Spirulina supplement level of 4.6 g Spirulina DM/kg W.day with a 2.3-fold higher DOM intake than Control steers. Rumen NH3-N concentrations reached 128 and 264 mg NH3-N/L for the US and Spirulina treatments with a significant increase in the concentration of branched-chain fatty acids for the Spirulina treatment. The minimum retention time of liquid (Cr-EDTA; 23 and 13 h) and particulate (Yb; 34 and 22 h) markers in the rumen were significantly lower for Spirulina compared with US and lower than unsupplemented animals at 24 and 34 h for Cr-EDTA and Yb, respectively. Spirulina could be provided safely at much higher N intakes than NPN supplements. The results suggest that, at an equivalent RDP supply, Spirulina provided greater increases than US in MCP production, EMCP and feed intake of Bos indicus cattle consuming low protein forage and could also be fed safely at higher levels of N intake.

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

“…It is interesting that the proportions of branched‐chain fatty acids and valerate were particularly high in some cases. Increased concentrations of branched‐chain fatty acids in the rumen fluid of cattle receiving microalgae have been reported before (Costa et al., ; Drewery et al., ; Lamminen et al., ; Panjaitan, Quigley, McLennan, & Poppi, ; Panjaitan, Quigley, McLennan, Swain, & Poppi, ). Lamminen et al.…”

Photosynthetic Microorganisms

“…Due to their high content and the amino acid pattern, they are good protein sources and commonly use as complementary dietary source, both directly as supplements in the form of tablets or powder, or as an additive in food and beverages (Tang and Suter 2011). Panjaitan et al (2014) noted protein-rich S. platensis algae supplementation increases microbial protein production and feed intake and decreases retention time of digesta in the rumen of cattle. This microalga is also capable to produce high amounts of γ-linolenic acid (GLA).…”

Challenges of beef cattle production from tropical pastures

“…A source of energy or protein of low cost and high yields is required if there is a major increase in production. There is emerging interest in crops such as fodder beet and cassava for high metabolisable energy and algae (Panjaitan et al, 2015;Costa et al, 2016) for protein in developing these new systems.…”