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Camelina sativa is an oilseed containing 35–40% oil. Feeding CC to food-producing animals is presently not allowed in Canada except for egg layers (10% inclusion) and broiler chickens (12% inclusion), which implies that the cake has otherwise limited economic value to oilseed crushers. The sale of the cake or solvent-extracted meal resulting from oil extraction into the animal feed sector would be a major revenue stream for commercial oilseed processors. In Canada, a prerequisite for listing of novel feedstuffs is the evaluation of data relating to feeding safety and efficacy. The purpose of this experiment was to generate information pertaining to the safety of feeding CC to broiler chickens at dietary inclusions up to 24%. The objectives were to evaluate the effect of feeding increasing dietary inclusions of CC on clinical appearance of organ tissues, as well as on organ weights, serological parameters, feed disappearance, and nutrient digestibility of CC.
Male chicks (n = 744; Ross 308) were brought to the Poultry Research and Technology Centre (Edmonton, Alberta, Canada) on the day of hatch. Chicks were then randomly distributed among 24 test cages (53.3 cm width × 119.4 cm length × 43.2 cm height) in a 3-tiered pullet battery for 31 chicks per test cage. Test cages were grouped into six blocks based on location within the test battery. Each dietary regimen appeared once per block for a randomized complete block design with six replicate cages per treatment. Beginning at placement (d 0), chicks had ad libitum access to phase diets corresponding to the dietary regimen assigned to each cage. Test diets included 0, 8, 16, or 24% CC for each of three, 2-week phases (starter, d 0–14; grower; d 15–28; finisher; d 29–42). Individual broiler weights were measured on d 0, 7, 14, 21, 28, 35, and 42. On d 21, 10 broilers from each test cage were euthanized by cervical dislocation and digesta was collected.
The two batches of CC averaged 34.3% CP, 26.5% NDF, 14.7% ADF, 9.4% CF, and 5.2% ash. Increasing dietary CC inclusion level did not affect broiler mortality, number of broilers culled, or gross post-mortem organ (thyroid, heart, liver, etc.) findings that might suggest toxicity. The results of this study also indicated that dietary inclusion of up to 24% CC does not affect the occurrence of gross pathological findings, most notably the thyroid, liver, and heart. The total incidence of Tibial Dyschondroplasia was greater among broilers fed either 16% or 24% CC compared with those fed 0% or 8% (P = 0.014). Dietary CC inclusion level affected broiler performance. Overall (d 0–42) average daily BW gain (ADG) increased linearly with increasing dietary inclusion of CC (P < 0.05). For all three phases of the study, ADG for broilers fed 0% and 24% CC was lower compared with those fed the 16% inclusion diet (P < 0.01). For most nutrients, apparent ileal digestibility was not different between broilers fed 8% and 16% CC, but was lower for those fed 24% CC inclusion (P < 0.01).
In conclusion, the results of the present study indicate that CC can safely be fed at dietary inclusions up to and including 24% without adverse effects on the mortality or indicators of toxicity in broiler chickens. Feed disappearance in the present study further suggests that CC was acceptable to broiler chickens up to 16% dietary inclusion. The present study, however, also underscores the need to better understand the advantages and limitations of dietary CC inclusion in order to optimize its use as a feedstuff for poultry. In particular, more data is needed regarding digestible nutrient content of CC for broiler chickens. Our finding of detectable levels of trypsin inhibitor in CC also suggest further investigations should be undertaken into the relative significance of anti-nutritive factors present in camelina cultivars. The effect that oil extraction conditions have on feeding value of the resulting CC for poultry also warrants further attention.