Exploring the Potential of Cannabis in Poultry Nutrition

Introduction

Cannabis sativa, commonly known as hemp, marijuana, or simply Cannabis, is an annual, oil-producing plant of the Cannabaceae family (Small & Cronquist, 1976). Its cultivation originated in China and later spread to the rest of the world (Vasantha Rupasinghe et al., 2020).

Cannabis cultivation

The Cannabis plant thrives in temperatures between 13 and 22 °C and adapts to various soil types, preferably deep, well-aerated soils with a pH close to 6 and good moisture and nutrient retention capacity. It is sensitive to compaction and waterlogging (Rehman et al., 2021).

For planting, conventional tillage is preferred, although “zero tillage” can be used, affecting seedling emergence. Irrigation and density are the main factors affecting plant productivity, whether for fiber or flower production (Rehman et al., 2021).

During the vegetative growth phase, the plant responds well to high temperatures, exhibiting rapid growth and increased water requirements. However, after developing the third pair of leaves, the plant can withstand temperatures as low as -0.5 °C for 4 or 5 days (Rehman et al., 2021).

 Medicinal cannabis

Cannabis, in its composition, contains around 500 different compounds, including flavonoids (cannaflavin and kaempferol), terpenes (limonene and α-pinene), phytocannabinoids (tetrahydrocannabinolic acid, cannabidiolic acid, cannabichromenic acid, and cannabigerolic acid), and phenols (Russo, 2011).

The most important and recognized compounds are tetrahydrocannabinol (THC), the psychoactive component, and cannabidiol (CBD), a non-psychoactive phytocannabinoid with antioxidant, anti-inflammatory, anxiolytic, and anticonvulsant effects (della Rocca & Di Salvo, 2020; Iffland & Grotenhermen, 2017; Lim et al., 2017; Shannon & Opila-Lehman, 2016).

Both THC and CBD are found in higher concentrations in flowers and leaves, and to a lesser extent in stems, with a higher concentration in female plants than in males (Espósito et al., 2021). Generally, varieties of Cannabis sativa with low THC content are referred to as “hemp,” while those with high THC content are called “marijuana.” Due to this, its cultivation has been prohibited in many countries, resulting in limited literature on its use in animal feed (Silversides & Lefrançois, 2005).

However, in recent years, its cultivation has been decriminalized for medicinal and/or recreational purposes (Cerino et al., 2021). As a result, the scientific community is seeking to improve Cannabis cultivation for increased CBD production and decreased THC content.

Use of cannabis in poultry nutrition

There is a growing interest in the use of Cannabis in animal feed, not only for its nutritional contribution (Kırkpınar et al., 2018) but also for the effects of various compounds present in this plant (Fallahi et al., 2022).

In poultry feed, seeds (Figure 1), oil, and by-products left after oil extraction can be used (Burton et al., 2022; House et al., 2010).

Figure 1. Images of (A) industrial Cannabis seeds; (B) shelled seeds. Source: (Shen et al., 2021).

The nutritional composition of Cannabis and its by-products can vary significantly (Table 1).

Table 1. Nutritional composition of Cannabis seed and its by-products Data on an as-is basis. ADF: Acid detergent fiber; NDF: Neutral detergent fiber; GE: Gross energy. (House et al., 2010).

The seed has a low content of phytic acid, condensed tannins, and trypsin inhibitors (Russo & Reggiani, 2015).

Previous research has shown that incorporating Cannabis seeds in poultry feed led to increased weight gain (Khan et al., 2010; Skřivan et al., 2020), along with an upregulation in the expression of genes associated with intestinal barrier function and enhanced activity of enzymes from intestinal bacteria (Konieczka et al., 2020).

On the other hand, the inclusion of Cannabis expeller in poultry feed has yielded contradictory results: in one study, 10%, 20%, and 30% inclusion of Cannabis expeller between 28 and 35 days of age showed no negative effects on productive parameters (Kalmendal, 2008), possibly due to the short supply time (one week). However, it reduced the digestibility of dry matter, which could be attributed to the high fiber content of the expeller, a situation that could be corrected by dehulling.

The fiber in Cannabis seeds can be divided into soluble and insoluble fiber; the former slows digestion by forming a gel in the intestine, while the latter adds volume to feces as it does not dissolve (Rehman et al., 2021).

In another trial, Cannabis expeller was provided at 5% and 15% inclusion between 12 and 37 days of age, and with 15% inclusion, the birds had lower weight and poorer conversion (Stastnik et al., 2015), possibly explained by the lower digestibility found by Kalmendal (2008). On the other hand, Eriksson and Wall (2012) added 10% Cannabis expeller at the start and 20% at the end, finding no differences in productive parameters, mortality, or microbiological aspects compared to the control group.

 organic farming practices, where the utilization of solvent-extracted meals, animal-derived protein sources, or synthetic amino acids is restricted, Cannabis seeds, like other oilseeds, serve as a viable alternative protein source. This is attributed to the excellent quality of their reserve proteins, specifically edestin and albumin, which are highly digestible and encompass all essential amino acids (House et al., 2010; Kırkpınar et al., 2018).

Both Cannabis oil and seeds are rich in omega-3 fatty acids, making it possible to transfer these fatty acids to egg yolk (Gakhar et al., 2012; Jing et al., 2017; Kasula et al., 2021; Silversides & Lefrançois, 2005) or chicken meat (Jing et al., 2017; Skřivan et al., 2020), similar to other plant sources of omega-3, such as chia and flax (Antruejo et al., 2011; Iglesias, 2010), and also serving as a source of antioxidants (Yu et al., 2005).

Limited evidence exists on this matter, and in a particular study, incorporating 0.3% Cannabis seeds did not result in enhancements in productive parameters. However, it did lead to a reduction in the levels of the serum enzyme aspartate aminotransferase (AST), which is employed to identify elevated hepatotoxicity and other liver diseases (Vispute et al., 2019). Additionally, as an extranutritional effect, it was observed that introducing 7.5% Cannabis seeds into the chicken diet resulted in decreased cholesterol and triglyceride levels in the bloodstream (Mahmoudi et al., 2015).

Conclusions

Cannabis seeds have acceptable nutritional value and can be added to poultry diets in various forms (whole seeds or expeller). However, fiber may interfere with the normal digestion process, prompting the possibility of working with dehulled Cannabis or limiting the intake of expeller. Moreover, due to its high content of omega-3 fatty acids, it is possible to produce functional eggs and meat.

In summary, the incorporation of Cannabis in poultry nutrition is viable; however, additional research is required to determine more suitable levels of inclusion and presentation.

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