+43 720 500 205
+49 89 2620 12 050
Insect protein: myths and facts – we look at a study.
Since the European Commission officially approved insects as food, countless pro and con opinions have been circulating online.
Attempts are being made to ban the valuable use of insect meal/protein from various insect species from the diet, despite opposing opinions, but does this also apply to animal feed?
It's important to note that the black soldier fly (Hermetia illucens) is only regulated by the Feed Act and is currently not permitted in food. According to Regulation (EU) 2017/893, insects are considered farm animals if they are used for the production of processed animal protein. This means that the feeding bans in Regulation (EC) 999/2001 and Regulation (EC) 1069/2009 also apply to insects, and no food scraps or ruminant proteins may be fed to farmed insects. This is not prohibited outside the EU. This is where the crux of the matter begins. Where does the insect protein come from? What was it fed? How are the insects processed before they are used in food or animal feed.
The production of entoVITAL Hermetia larvae?
Our Austrian larvae, sourced from sustainable recycling, are washed and inactivated during growth under strict regulatory requirements, ensuring no contamination. Inactivation is also a sanitization or sterilization process. Furthermore, our larvae contain only 2% chitin before the pupal stage. Through countless tests and trials with universities of applied sciences, we have been able to determine the best pupal stage for further processing into animal feed.
We can also separate our larvae from the chitin, as valuable chitin is often seen as a sustainable alternative in the cosmetics and packaging industries. Thus, not all insect proteins are created equal.
We've had insects on our menu for a long time - did you know this fact?
Scarlet scale insects and lacquer scale insects have been used in the food industry for much longer.
For example, a red dye called " red carmine ," " E120 ," is extracted from the scarlet scale insect. Pregnant insects are dried and boiled, and this substance is often used in sweets. In cosmetics, this extracted substance is listed as " carmine ," " CI 75470, " or " conchicine ."
Shellac, in turn, is obtained from the secretions of lac insects. Shellac forms a glossy coating – its uses range from paints and varnishes to nail polish, hairspray, and, as an additive for sweets, under the code " E904 ".
Do Hermetia larvae feel like humans?
Hermetia larvae do not have a brain or a central nervous system as we know it, so these creatures do not feel like other animals or humans.
Myth: Hermetia illucens have “antinutrients” to protect against predators?
This isn't the case with the larvae of Hermetia illucens, as they are also eaten by their fellow insects, including chickens and other animals. Their natural metabolism eliminates anything harmful. Not all insects are created equal.
Myth: Insects aren't healthy? Is insect protein really such a bad thing?
As described in the inaugural dissertation of Dr. Heide in 2017 at the Free University of Berlin under the supervision of Univ.- Prof. Dr. Zentek: Larval meal of Hermetia illucens as a protein carrier in dog food, we now devote ourselves to the topic.
What was the topic of this dissertation?
The chitin content and digestibility of chitin were determined, as well as whether the chitin content in the feed has an effect on enzymatic processes, especially on chitinase activity in the dog's digestive tract.
The total amount of feces per day was used to determine the apparent total digestibility of nutrients and the chlorine utilization.
Chitinase content in feces was determined using a color reaction. When chitinase converts colloidal chitin into azure, the azure pigment is released and can be measured photometrically at 560 nm.
Chitin is a polysaccharide composed of N-acetyl-D-glucosamine units. Both blood and feces were analyzed to evaluate digestive physiological parameters, bacterial metabolites, determine chitin content, and measure chitinase activity.
None of the dogs showed any health problems during the experiment or had to be removed from the test series, which can generally be considered a positive thing.
However, the dry matter content of the feces did not differ between the two feeding groups. Hematological parameters did not differ between the two feeding groups, and the differential blood count also showed no differences; all parameters were within the normal range. There were also no statistically significant differences in the lymphocyte populations between the two feeding groups during the trial.
The food antigen-induced lymphocyte proliferation test showed no differences in the stimulability of the lymphocytes (stimulation index) between the two feeding groups.
The difference in the analysis revealed that the apparent dry matter digestibility of potassium, zinc, phosphorus, and sodium was higher in the dogs fed the experimental diet. The apparent digestibility of calcium, magnesium, and iron was higher in the control group.
The concentrations of acetic acid and total fatty acids in the feces were higher in the dogs fed the control diet.
No differences were detected in the distribution of short-chain fatty acids in the faeces between the feeding groups.
Neither D- nor L-lactate concentrations in the feces differed significantly between the two feeding groups.
A difference in fecal ammonium concentration was demonstrated between the two feeding groups. The control group showed higher fecal ammonium levels.
Chitinase activity in the stool sample
When comparing the chitinase activity in the feces of both feeding groups, no difference was found.
Chitin content in feed and faecal samples
The chitin concentration (in g/kg DM) in the dogs' feces differed between the two feeding groups. The chitin concentration in the feces of the experimental group was significantly higher than in the control group.
Blood count and differential blood count
To assess the dogs' health during the trial, a complete blood count, including a differential blood count, was performed. The results show no feeding-related differences between the two diets, and all values are within the reference range. Swanson et al. (2004) compared a plant-based and an animal-based diet over a period of 12 months.
In this study, no feeding-related difference between erythrocytes, hematocrit, and hemoglobin was observed.
Total digestibility
The higher the crude fiber content of the ration, the lower the apparent digestibility of organic matter. The nature of the plant cell wall components is also crucial. Compared to the control diet with lamb as the protein source, the experimental diet had higher apparent digestibility of organic matter, dry matter, and crude ash. In contrast, the apparent digestibilities of crude fiber, crude fat, and crude protein were higher when fed the control diet.
Both feeds also contained other protein sources, so the apparent digestibility cannot be related solely to the main protein sources. Furthermore, the crude fiber and crude ash values of the two feeds differ, so the apparent digestibility of these crude nutrients is only comparable to a very limited extent.
Bacterial metabolites in the stool samples
There were some differences in the fecal concentrations of short-chain fatty acids and ammonium levels between the feeding groups. The lactate levels measured in the feces of the test animals in this study showed no feeding-related influence.
Short-chain fatty acids
Despite the higher crude fiber content of the experimental diet containing Hermetia illucens in the present study, no higher levels of short-chain fatty acids were observed in the feces of the dogs fed this diet. In general, the results for short-chain fatty acids indicate that greater fermentation occurred in the large intestine of the dogs after feeding the control diet. However, the percentage distributions of short-chain fatty acids, relative to the total fatty acids, are comparable to other studies (Middelbos et al., 2007; Sunvold et al., 1995).
Ammonium and feces
If increased amounts of protein enter the large intestine, microbial fermentation processes produce end products such as ammonia or ammonium (Meyer and Zentek, 2013). Beloshapka et al. (2016) also observed decreasing ammonium concentrations in dog feces with increasing soybean meal levels in the diet.
The highest fecal ammonium content was found in dogs fed poultry by-products as their primary protein source. Ammonium concentration, or ammonia absorption, depends on intestinal pH. Furthermore, the rate of ammonium production and thus the fecal concentration also depends on the colonic microbiota and available energy (Hesta et al., 2003).
Chitinase activity in the stool sample
There are studies in which the chitin content in insects was measured using gravimetric methods (Lovell et al., 1968). Since the chitin content in feces and food is very low, in contrast to the chitin content in insects, a new method using ion chromatography was evaluated for the present study. Chitin is a polysaccharide composed of N-acetyl-D-glucosamine units.
The glucosamine produced by hydrolysis is thus related to the chitin content in the samples. The more chitin in the diet, the lower the digestibility of chitin. In the present study, it remains questionable why glucosamine was measured in the control diet and in the feces of the dogs fed the control diet. It is likely that the control diet contained N-acetyl-D-glucosamine in the form of other polysaccharides and not in the form of chitin. N-acetyl-D-glucosamine is a component of some glycosaminoglycans such as hyaluronic acid, heparan sulfate, and keratan sulfate.
These glycosaminoglycans are found in synovial fluid, blood vessels, cartilage, the cornea, and the nucleus pulposus (Thonar et al., 1985). The detection of glucosamine after feeding control food can presumably be explained by the fact that it was not chitin, but other polysaccharides containing N-acetyl-D-glucosamine.
Chitin content in feed and feces samples
The question of whether dogs produce the enzyme chitinase and whether its activity is increased by chitin intake should be clarified by examining chitinase activity. Lundblad et al. (1974) already demonstrated chitinase activity in the serum of goats, cows, chickens, sheep, and pigs. No chitinase could be detected in the serum of humans, monkeys, horses, cats, dogs, rabbits, hamsters, or guinea pigs. This chitinase plays a role, among other things, in the defense against chitin-containing bacteria (Suzuki et al., 2002). Chitinolytic enzymes in the digestive tract can be produced by the animal itself, derived from its feed, or synthesized by the microbiota (Simunek et al., 2001). In a study by Koh and Iwamae (2013), the activity of the enzymes chitinase and N-acetyl-β-D-glucosaminidase, which are present in the mucosa of the glandular stomach and in various segments of the small intestine, was examined after feeding a chitin-containing diet and a control diet. Enzyme levels did not increase with the chitin-rich diet.
The aim of this study was to determine whether dogs produce the enzyme chitinase in their gastrointestinal tract and whether the enzyme's production is increased by chitin-containing food. Chitinase activity of 0,12 units was measured in the feces of the control group. The results thus provide evidence that chitinase activity exists in the digestive tract of dogs, but that it is not increased by chitin-containing food, as a similar activity was measured in the test group. Thus, the chitin-containing test food did not promote bacterial chitinase activity.
Further studies could clarify whether chitinase is constitutively present in the gastrointestinal tract of dogs. Since chitinase was detected in the dogs' feces, it is also possible that the actual amount of chitinase was no longer detectable in the feces if chitinase production occurred in the stomach or small intestine, and the enzyme was potentially degraded during passage through the large intestine.
Conclusion
The results demonstrated a similarly high apparent digestibility of the raw nutrients compared to a commercial complete feed with lamb as the main protein source.
The present results show no evidence of intolerance, so that the use of the investigated larval meal as a protein component in the diet of dogs is possible.
No immunological or hematological differences were detected between the two feeding groups. Examination of the concentrations of microbial metabolites in the fecal samples revealed higher concentrations of short-chain fatty acids and ammonium in the feces of the dogs after consuming the control diet. As expected, more chitin was detected in the experimental diet than in the control diet. Chitinase activity in the feces was not affected.
In this study, no negative effects of the test feed containing Hermetia illucens larval meal were detected in dogs in the feeding trial, so that good tolerance can be assumed within the dosage range investigated.