Influence of hempseed cake inclusion on growth performance, carcass characteristics, feeding behavior and blood parameters in finishing heifers

Feeding hempseed cake alters the bovine gut, respiratory and reproductive microbiota

A growing number of studies have investigated the feasibility of utilizing hemp by-products as livestock feedstuffs; however, their impact on livestock microbiomes remains unexplored. Here, we evaluated the effects of feeding hempseed cake on the gastrointestinal, respiratory, and reproductive microbiota in beef heifers. Angus-crossbred heifers (19-months old, initial body weight = 494 ± 10 kg [SE]) were fed a corn-based finishing diet containing 20% hempseed cake as a substitute for 20% corn dried distillers' grains with solubles (DM basis; Control; n = 16/group) for 111 days until slaughter. Ruminal fluid and deep nasopharyngeal swabs (days 0, 7, 42, 70 and 98), and vaginal and uterine swabs (at slaughter) were collected, and the microbiota assessed using 16S rRNA gene sequencing. Diet affected the community structure of the ruminal (d 7-98; 0.06 ≤ R² ≤ 0.12; P < 0.05), nasopharyngeal (d 98; R² = 0.18; P < 0.001), and vaginal (R² = 0.06; P < 0.01) microbiota. Heifers fed hempseed cake had increased microbial diversity in the rumen, reduced microbial richness in the vagina, and greater microbial diversity and richness in the uterus. In addition to the distinct microbial communities in the rumen, nasopharynx, vagina and uterus, we identified 28 core taxa that were shared (≥ 60% of all samples) across these sampling locations. Feeding hempseed cake appeared to alter the bovine gut, respiratory and reproductive microbiota. Our results suggest that future research aiming to evaluate the use of hemp by-products in livestock diet should consider their impact on animal microbiome and microbiome mediated animal health and reproductive efficiency. Our findings also highlight the need for research evaluating the impact of hemp-associated food and personal care products on the human microbiome.

Effects of hempseed cake on ruminal fermentation parameters, nutrient digestibility, nutrient flow, and nitrogen balance in finishing steers

Five ruminally and duodenally cannulated red angus steers (n = 5; initial body weight [BW] = 542 kg, SD = 40 kg) were used in a three-period Youden square design consisting of three 21-d periods, three treatments, and five steers (one or two steers per treatment within each period) to evaluate the effect of feeding hempseed cake on ruminal fermentation parameters, organic matter (OM) intake, total tract nutrient digestion, and nitrogen (N) balance in steers fed finishing diets. The control (CON) diet contained 75% dry-rolled corn, 20% corn silage, and 5% supplement (DM basis). The dried corn distillers grains plus solubles (DDGS) and hempseed cake (HEMP) diets contained 55% dry-rolled corn, 20% corn silage, 20% dried corn distillers grains plus solubles or hempseed cake, and 5% supplement (DM basis). Total ruminal volatile fatty acid concentration was greater (P < 0.01) in steers fed the HEMP diet than in steers fed the DDGS or CON diets. Ruminal fluid pH was not influenced (P = 0.93) by treatment. Organic matter intake tended (P = 0.07) to be greater and OM total tract digestibility was less (P = 0.03) in steers fed the HEMP diet compared with steers fed the DDGS or CON diets. Ruminal true and total tract apparent N digestibility was greater (P < 0.01) in steers fed the HEMP diet than steers fed the DDGS or CON diets. Duodenal flow of essential, nonessential, and total amino acids was not influenced (P ≥ 0.37) by dietary treatment, but the lack of response was likely because ruminally degradable protein (RDP) supply exceeded the RDP requirement. Steers fed the HEMP diet had greater (P < 0.01) N retention (g/d) than steers fed the DDGS diet, which was greater (P < 0.01) than steers fed the CON diet, suggesting that feeding hempseed cake improved utilization of N. Although inclusion of hempseed cake decreased total tract OM digestibility compared with dried corn distillers grains or corn, improvements in N utilization suggest that hempseed cake could be a useful alternative feed ingredient for finishing cattle diets.

Rapid quantification of cannabinoids in beef tissues and bodily fluids using direct-delivery electrospray ionization mass spectrometry

Hempseed cake is a byproduct of hempseed oil extraction and is potentially a useful source of protein and fiber for use in ruminant diets. However, data are lacking on the appearance and/or clearance of cannabinoids in tissues of animals fed hempseed cake. To this end, a rapid method for quantifying cannabinol (CBN), cannabidiol (CBD), cannabinolic acid (CBNA), cannabidiolic acid (CBDA), cannabigerolic acid (CBGA), cannabichromenic acid (CBCA), cannabidivarin (CBDV), cannabidivarinic acid (CBDVA), tetrahydrocannabinol (THC) and tetrahydrocannabinolic acid (THCA) in cattle tissues, plasma, and urine was developed using rapid screen electrospray ionization mass spectrometry (RS-ESI-MS). Regression coefficients of matrix-matched standard curves ranged from 0.9946 to >0.9999 and analyte recoveries averaged from 90.2 ± 15.5 to 108.7 ± 18.7% across all compounds. Limits of detection and quantification ranged from 0.05 to 2.79 ng · mL^-1 and 0.17 to 9.30 ng · mL^-1, respectively, while the inter-day relative standard deviation ranged from 5.1 to 15.1%. Rapid screening electrospray ionization mass spectrometry (RS-ESI-MS) returned no false positives for any cannabinoid in plasma, urine, and tissue (liver, skeletal muscle) samples from 6 non-dosed control animals (n = 90 samples; of which 72 samples were plasma or urine and 18 samples were tissues). Across-animal cannabinoid concentrations measured in 32 plasma samples of cattle dosed with ground hemp were quantified by RS-ESI-MS; analytical results correlated well (r² = 0.963) with independent LC-MS/MS analysis of the same samples.