Laboratory tasks related to feed in vivariums include studies aimed at assessing feed quality, determining nutrient content, and controlling safety. These tasks are important because the health status and weight gain of laboratory animals depend on the balance and quality of the feed.

Small laboratory animals are the most common model for studying various processes in biomedical research. To obtain high-quality and reliable research results, special attention must be paid to the composition and quality of the feed that animals receive during breeding and housing in vivariums. This ensures growth, reproduction, and response to pathogenic microorganisms or various stress situations arising from manipulations and experimental interventions.

Currently, mouse feeds intended for research purposes are produced industrially, where food safety is ensured by analyzing and controlling all biological and chemical materials used to formulate various feed recipes. Mouse feeds must have reliable labeling containing information about all ingredients. For feed production, food-grade raw materials must be used, the quality and safety of which comply with the requirements established in accordance with the legislation of the Russian Federation for food production. This is necessary to ensure the reproducibility of animal research results. For scientific research using small laboratory animals, it is recommended to use feeds with a standardized composition for each ingredient.

At the end of the last century, the American Institute of Nutrition proposed using purified ingredients to create a standard open-formula feed for studying all aspects of normal and pathological conditions in animals. For example, the AIN-76A standard diet was adopted for rodents, where protein requirements are met by casein milk protein with added methionine. Carbohydrates, in this case, are supplied by corn starch and sucrose, corn oil provides fat requirements, and cellulose is a source of fiber. Vitamins and minerals are added in proportions specific to rodents. Since the formula of such a feed is “open,” it can be accessible to the scientific community, making it possible to reproduce and modify it by adding other nutritional components.

• Use of feed standardized by each ingredient for any in vivo experiments
• Pharmacology
• Toxicology
• Oncology
• Cell Therapy
• Creation of specialized animal models
• Cardiovascular function research
• Obesity research

Based on research, a standardized semi-synthetic complete pelleted feed LUMINON™ was created with optimal amounts of vitamins, micro- and macroelements, proteins, and fats. The feed is balanced with vitamins and trace elements, is allergen-free, has a sufficient concentration of easily digestible carbohydrates, and a metabolic energy value of at least 3800 kcal/kg. The feed composition is designed for ad libitum feeding of rodents of all ages. An additional advantage of the semi-synthetic feed is the absence of an autofluorescence signal during in vivo optical imaging experiments, which prevents short-term fasting of small laboratory animals before experiments.

The composition and quality of feed for small laboratory animals determine not only the health status of the animals but also the quality of data obtained in in vivo experiments. For reproducibility of data in scientific research, it is recommended to use feeds with a standardized composition for each ingredient. In studies using in vivo imaging methods, the absence of autofluorescence in the feed, which can significantly distort the obtained results, is also very important.

In vivo optical imaging of fluorescent signals (FLI) allows non-invasive assessment of marker distribution in small laboratory animals. The method is versatile due to the possibility of using various fluorescent probes, which allows detecting cell populations, visualizing tumors using fluorophore-labeled antibodies and peptides, mapping lymph nodes, and visualizing enzymatic activity. Although light scattering and absorption limit its penetration through tissues, light in the 600-900 nm wavelength range, i.e., far-red and near-infrared (NIR) light, can travel relatively long distances in living tissue and is suitable for optical imaging. Therefore, for this technology in model systems, researchers try to use fluorophores that emit light in the far-red and near-infrared regions of the electromagnetic spectrum. However, when detecting a fluorescence signal from the studied fluorophore, autofluorescence from the animal’s surface always occurs. This effect is observed even without the introduction of exogenous fluorescent probes. Autofluorescence creates a background signal that, in some situations, can cause serious problems. Strong autofluorescence with a peak wavelength of about 680 nm is always observed in the mouse abdomen due to the presence of chlorophyll and its metabolites in the intestine. Autofluorescence in the intestine can mask or suppress the signal from the studied fluorescent probes localized in or near the abdomen, and also mimic the excretion and/or accumulation of probes in the intestine.

Standard rodent feeds contain a large amount of alfalfa and, consequently, chlorophyll. In feed that does not contain alfalfa, the chlorophyll content is minimal or absent. Mice fed alfalfa-free feed for 1-2 weeks show a decrease in abdominal autofluorescence; such feed can be used for optical experiments. However, even with an alfalfa-free diet, intestinal autofluorescence remains more intense than autofluorescence of other organs.

Semi-synthetic feed, free of chlorophyll, reduces autofluorescent signals in the intestine. A relative comparison of abdominal autofluorescence in mice using different feeds was conducted, showing an increase in autofluorescence intensity in animals receiving conventional feed, while animals receiving alfalfa-free semi-synthetic feed had virtually no autofluorescence.

The goal of developing LUMINON™ semi-synthetic feed, which does not contain alfalfa and chlorophyll, is to reduce intestinal autofluorescence and standardize the animal’s diet throughout the experiment.

Composition of semi-synthetic feed