LabDiet - Resources

PRODUCT BROCHURES

FORMULATION FACTS

Biomedical researchers advance science through experimental research conducted with animal models. Accurate results and meaningful conclusions are achieved only when tight control is maintained over all materials and methods used in every research study. The animal diet is a key variable that must be controlled and managed to minimize changes over time.

Variation in natural ingredient diets fed to animals involved in biomedical research could confound experimental results or influence the interpretation of results. Therefore, it is important to manage diet formulas and have tight controls when manufacturing the diet. In fact, it is unlikely that lots manufactured according to the same formulations would contain exactly the same concentrations of nutrients or contaminants as different batches of ingredients may be used.²

Three common practices used to formulate and manufacture animal diets including Managed Formulation (delivering CONSTANT NUTRITION^®), Fixed Formulation, and Least-Cost Formulation, which are detailed below.

Facts on Animal Feed Formulation

PRODUCT STABILITY

How Storage Conditions, Product Stability, and the Manufacturer's Warranty Work to Determine your LabDiet® Shelf Life.

Effects of Temperature and Humidity on Diet Stability During Transit to the United Kingdom followed by 18 Months of Storage at IPS (2020)

Effect of trans-Pacific transport and storage time on macro- and micro-nutrient concentrations of LabDiet® PicoLab® Rodent 20, 5053, LabDiet® PicoLab® Mouse Diet 20, 5058, and LabDiet® Monkey Diet, 5037, for 24 months post-manufacture (2015).

Effect of Irradiation on Microbiological Activity of Grain-based and Purified Diets Manufactured by LabDiet® or TestDiet® (2015).

Effect of Storage Time on Macro- and Micronutrient concentrations of LabDiet® Mouse Diet, 5015, and PicoLab® Rodent Diet 20, 5053 (2011).

Effect of Storage Time on Macro- and Micronutrient concentrations of LabDiet® New World Primate Diet, 5040, and High Protein Monkey Diet, 5045/5047 (2011).

Effect of Storage on the Vitamin Levels of Pelleted LabDiet Guinea Pig Diet 5025 (2007).

Effect of Storage Time and Temperature on the Vitamin Levels in LabDiet® Certified Rodent Diet 5002 (1998).

AUTOCLAVING LABORATORY DIETS

LabDiet^® offers a multitude of Autoclavable laboratory animal diets. Steam autoclaving of laboratory diets has been performed for laboratory animals for many years. The purpose is to lower the microbiological load on the food. Autoclaved food is a means to feed animals kept behind bio-secure barriers that cannot be exposed to the natural microbiological load found on most natural-ingredient diets.

It is critical when autoclaving diets that care has been taken to compensate for heat-sensitive nutrients that may be degraded during the heating process. If one autoclaves a diet that was not formulated specifically for heat-treatment, there is a strong possibility that deficiencies can occur. In addition, it is very important to note that you should NOT feed a diet that is formulated for autoclaving in an un-autoclaved manner.

Different techniques can be used in preparing the diet for autoclaving. The diet can be placed in trays, re-packaged into 3-4 pound (1.4-1.8 kg) paper bags, or the original bag of food can be perforated to allow improved steam penetration. Bags should be arranged in the autoclave so all sides are free to allow steam penetration.

Adjust steam jacket pressure to normal. Place the desired volume of diet in autoclave, and pull a vacuum of 26-28 inches (660-711 mm) of mercury, or until completely void of air. Begin metering in the steam slowly while pulling vacuum. The temperature should reach 190ºF (88ºC) in 10-15 minutes. Take caution the diet does not become too wet with condensate or trapped water. Turn off the vacuum and allow entry of full steam volume.

The length of time and temperature will determine the degree of sterilization. Pasteurization will occur in 12-15 minutes at 250ºF (121ºC); sterilization in 20-25 minutes at 250ºF (121ºC) after pressure has reached 15 PSI.

Close steam and slowly open chamber exhaust. Vent to 2-5 PSI. Turn on vacuum and pull 20-25 inches (508-635 mm) of mercury. Drying time depends on quantity of diet and chamber volume, usually about 30 minutes.

In order to ascertain the microbiological status of the food, a microbiological culture will be required. This will give information regarding bacterial, viral and mold contaminants that might remain intact. Indicator strips are available to determine degree of sanitization that have been done on the food.

Samples of diet should be taken pre- and post-autoclave in order to assay the sentinel vitamins, A and thiamine. They are among the more heat-labile vitamins and analysis will give an indication if under- or over-heating has occurred.

The table below is an example of the effects different temperatures and exposure times has on autoclavable diets.

EFFECT OF VARYING TIME AND TEMPERATURE ON STERILIZATION OF PURINA AUTOCLAVABLE LABORATORY DIET
TEMP DEG (F)	TIME MIN	THIAMIN PPM	PERCENT RETAINED	VIT. A IU/G	PERCENT RETAINED	BACTERIA RETAINED
--	0	73.8	--	30.3	--
250	5	67.1	90.9	28.1	92.7	GRAM (+) BACILLUS GRAM (-) RODS MICROCOCCUS
250	10	60.3	81.7	24.3	80.2	GRAM (+) BACILLUS
250	15	60.8	82.4	23.1	76.2	GRAM (+) BACILLUS
250	20	36.4	49.3	19.2	63.4	STERILE
250	25	31.2	42.3	14.7	48.5	STERILE
250	30	23.4	31.7	12.8	42.2	STERILE
270	5	55.6	75.4	28.1	92.7	GRAM (+) BACILLUS
270	10	16.2	22.0	10.3	34.0	STERILE
270	15	21.3	28.9	11.4	37.6	STERILE
270	20	16.1	21.8	12.4	40.9	STERILE

Tests in duplicate. Purina Autoclavable Laboratory Diet is fortified to be autoclaved using the following procedure:Place 1-2 lb. of product in small bag or layer in trays 1-2 inches deep.Pull a vacuum, 26-28 inches of mercury, for 5 minutes.Sterilize at 250 deg F at 15 lb. pressure.Maintain temperature for 20 minutes.

Product Support Materials

Product Standards

A well-balanced diet, along with plenty of clean, fresh water, is essential for proper animal health. TestDiet^® manufactures an extensive line of animal diets for research purposes, each carefully formulated to accommodate the nutritional requirements of laboratory animals. These requirements, the major components of food, are briefly described to provide an overview of basic animal nutrition.

Good Nutrition is Vital.

Good nutrition, including all of the essentials discussed here, is the only way to ensure the proper growth, reproduction, maintenance and overall health of the animals you depend upon for reliable research results.

Storage conditions as well as dietary characteristics affect the nutrient stability of laboratory animal diets. Such non-dietary factors include, but may not be limited to, lighting, oxygen, temperature and moisture. Antioxidants and fat in diet formulations can also affect the overall stability. Our extensive data prove that the manufacturers’ warranty of LabDiet® products can be extended beyond the recommendations in the Guide for Care and Use of Laboratory Animals by storing products under climate-controlled conditions. Irradiation can also extend the stability of a diet preventing growth of bacteria, yeasts and molds. Extension of your diet usage by controlled storage varies depending on the type of diet. The recommended shelf life based on proved product stability data for our LabDiet® and TestDiet® products is provided below. Click here for a quick-reference table along with a detailed description of each category of our products.

Each nutritional component has a specified unit of measurement. When the notation "ppm" is used, the component is being measured in parts per million. Parts per million is also sometimes referred to as milligrams per kilogram, or mg/kg. Some components are measured in micrograms per kilogram, or mcg/kg or ug/kg. Micrograms per kilogram is equivalent to the notation "ppb" or parts per billion.

In some cases the old values for nutritional components have been changed. To prepare for this revision, information was obtained from a number of sources (including the National Research Council, personal conversations with prominent researchers in the field and others) and was then compiled for your quick reference.

When data on a particular nutrient was scarce or unavailable, the ingredients were assayed. Our computer system was then updated, using this information, and recalculated the chemical composition of all of our products. The reported figure on the nutritional composition of the diets is determined by calculating the level of each nutrient contributed by each of the ingredients using a computer matrix. These values are checked occasionally by an analytical laboratory. As a result, the information in this revised version is the most accurate, and current available.

Affiliations

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Full Map available at AALAS.org.

Magazines:

Lab Animal
Comparative Medicine
JAALAS (Journal of the American Association for Laboratory Animal Science)
Journal of Nutrition
LAMA Review
The Enrichment Record

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Technical Info And Research

THE FACTS ABOUT ISOFLAVONES: A LOOK AT THE BIG PICTURE

Isoflavones, the most common form of phytoestrogens, are detectable in most all diets fed to laboratory animals. Isoflavones are not bad for animals; however more and more researchers need to verify the levels contained in the diets for specific study area. Before making your decision about isoflavones, there is more that you should know.

FACTS ON ISOFLAVONES IN DIETS

Click the link below to find information to assist you in making the correct choice for your lab animals.

Isoflavones (IF) are a common class of phytoestrogens. They are plant-derived compounds capable of estrogenic or antiestrogenic effects on the animals consuming them. Isoflavones are structural mimics of endogenous 17ß-estradiol (Seielstad, et al., 1995).
IFs are nothing new. As early as the 1920s, IFs were found to affect body metabolism and in the 1940s, IFs found in red clover were found to affect sheep fertility.
Since the early 1990s, with an increase in endocrine disruptor (ED) awareness, IFs have been identified as contributing factors that may affect the outcome of such studies.
In the lab community, some advocate feeding low IF diets to all of their animals. However, others feel the low IF diets should only be used where appropriate.

THE FACTS ABOUT ISOFLAVONES: A LOOK AT THE BIG PICTURE

Nutrient and Contamination Levels in LabDiet^® Certified Laboratory Animal Feeds

Based on data compiled from 1993-2012 by Purina LabDiet^® and in conjunction with an independent laboratory.

Animal diets used in laboratory studies must provide consistent and proper nutrition.¹ To assist in experimental control, feed manufacturers must ensure that all batches of feed meet approved nutritional profiles.² Certified diets for laboratory animals are commonly used in toxicological studies where control of contaminants, such as pesticides and heavy metals, is imperative. Certified LabDiet^® products manufactured by PMI are analyzed prior to sale and guaranteed not to exceed established maximum concentrations of key contaminants. PMI controls variables that could adversely affect study animals and possibly lead to inaccurate conclusions. Certified LabDiet^® products meet the recommendations of the FDA's Good Laboratory Practices Program.

This report is an update to our 2007 published bulletin "Nutrient and Contaminant Levels in LabDiet^® Certified Laboratory Animal Feeds: 15-Year Technical Bulletin" which reports the results of our ongoing efforts to provide diets that are consistent from batch to batch as well as year to year. The data reported in this bulletin includes that from 1993 to 2007 and now 2008 to 2012.

20-YEAR TECHNICAL BULLETIN UPDATE