PORTO, PORTUGAL and STUTTGART, GERMANY — Recent research from scientists in Portugal and Germany, published in Frontiers in Veterinary Science, dove deep into two novel protein sources for use in pet food. According to the study’s results, squid meal and shrimp hydrolysate show promise as protein sources in dog food.

With the global pet population rising, sustainability and environmental concerns remain ever-present for consumers. Marine byproducts that are rich in protein may help to address these concerns by reducing negative impacts on the environment, decreasing waste and improving economic efficiency.

The research evaluated two marine byproducts, squid meal and shrimp hydrolysate, as protein sources in dog foods. The squid meal was provided by Madrid-based Inproquisa and was a byproduct from the canning industry. The shrimp hydrolysate was provided by Elven, France-based Symrise Aqua Feed. Both byproducts were used in dry powder formats.

During the study, 12 Beagles were fed a standard commercial dog food (basal diet), a diet made with squid meal, or a diet made with shrimp hydrolysate. Additionally, two in vivo digestibility trials were conducted in which the dogs were fed varying inclusion levels of 50, 100 and 150 grams per kilogram of squid meal or shrimp hydrolysate in three periods, consisting of 10 days each.

The researchers evaluated apparent total tract digestibility (ATTD), metabolizable energy content, fecal characteristics, metabolites and microbiota. The squid meal and shrimp hydrolysate protein sources showed higher protein and methionine contents compared to traditional ingredients used in a dog food formula, and the shrimp showed higher antioxidant activity compared to the squid meal.

“First approach and taste were not affected by the inclusion of protein sources, but animals showed a preference for the basal diet,” the researchers wrote. “Effects on nutrient intake reflected the chemical composition of diets, and fecal output and characteristics were not affected by the increasing inclusion levels of both protein sources.”

Additionally, the researchers noted that the squid and shrimp byproducts resulted in higher ATTD of dry matter for most nutrients and energy compared to the traditional diet, suggesting that these novel protein sources might be a fit for highly digestible formulas. The inclusion of squid meal was found to decrease butyrate concentration, whereas the shrimp increased all volatile fatty acids except butyrate.

According to the research, fecal microbiota remained unaffected by the inclusion of squid meal, however, shrimp hydrolysate was found to have significantly affected anaerobic bacteria Oscillospiraceae, Firmicutes and Lactobacillus.

Regarding palatability, the researchers found that no food refusal was observed for any of the diets. However, palatability was negatively affected by the inclusion of 150 grams per kilogram of shrimp hydrolysate or squid meal.

“This result was unexpected as both squid meal and shrimp hydrolysate presented high levels of glutamic and aspartic acids, two amino acids found in various foods, including seafood, known to induce umami, a taste highly attractive to dogs,” the researchers wrote.

“Overall, results suggest that squid meal and shrimp hydrolysate constitute novel and promising protein sources for dog food, but further research is needed to fully evaluate their functional value,” they concluded.

Read the full study here.

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