Meta-Analysis of Incorporating Camelina and Its By-Products into Ruminant Diets and Their Effects on Ruminal Fermentation, Methane Emissions, Milk Yield and Composition, and Metabolic Profile


Riaz R., Waqas M., Ahmed I., Nouman H. M., Imtiaz B., Ul Hassan M., ...More

Fermentation, vol.11, no.10, 2025 (SCI-Expanded, Scopus) identifier identifier

  • Publication Type: Article / Article
  • Volume: 11 Issue: 10
  • Publication Date: 2025
  • Doi Number: 10.3390/fermentation11100593
  • Journal Name: Fermentation
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: antioxidant status, Camelina sativa, dry matter intake, fatty acid profile, meta-analysis, methane emissions, milk composition, oilseed by-products, rumen fermentation, ruminant nutrition
  • Ankara University Affiliated: Yes

Abstract

The incorporation of Camelina sativa and its by-products (oil, meal, seeds, and expellers) into ruminant diets improves feed efficiency and reduces environmental impacts. This systematic review and meta-analysis, conducted in line with PRISMA guidelines, identified 79 studies, of which 8 met strict inclusion criteria, yielding 23 comparisons. Data were analyzed using random-effects models in R with additional meta-regression and sensitivity analyses. Camelina supplementation significantly reduced dry matter intake (DMI; MD = −0.63 kg/day, p = 0.0188) with high heterogeneity (I2 = 98.6%), largely attributable to product type and dosage. Although the pooled effect on daily milk yield was non-significant (MD = −1.11 kg/day, p = 0.1922), meta-regression revealed a significant positive dose–response relationship (β = 0.3981, p < 0.0001), indicating higher milk yield at greater Camelina inclusion levels. Camelina oil and its mixtures reduced rumen pH and methane emissions, consistent with polyunsaturated fatty acid (PUFA)-mediated suppression of methanogenesis. Impacts on milk fat and protein are inconsistent, but improvements in unsaturated fatty acid profiles, including omega-3 and conjugated linoleic acid (CLA), have been reported. Camelina also lowered milk urea (MD = −1.71 mmol/L), suggesting improved nitrogen utilization. Despite promising outcomes, substantial variability and limited sample sizes restrict generalizability, underscoring the need for standardized, long-term trials.