Other Food Supplements
Lab blocks are best used as a supplement to the main diet. They should never be used as the sole source of food, simply because this is far too boring a staple for an animal that feeds on a wide variety of foodstuffs and enjoys exploration and foraging for different foodstuffs.
They are often used to supplement feeds when their keepers are on short holidays. They are nearly always the number one choice staple used for lab gerbils. This is because it is homogenised and researchers know that each gerbil in the study is being given exactly the same diet. Often if a diet is varied it would allow different gerbils to eat the different foods available, which could alter the results of an experiment. There are several lab blocks available and some designed specifically for gerbils. LabDiet, a branch of Purina, make over a 100 different types of lab block. The LabDiet website gives a lot of information on their products and distributors on their website.
With a good diet these are not needed nutritionally, however they can be added for several reasons. The block is often hard and apart from providing vitamins and minerals, it helps keep their teeth in trim. Also pregnant/ nursing females will appreciate the extra source of calcium, which is needed for the production of milk. Powders of calcium and/or other vitamins and minerals can be useful for adding to the regular food of nursing animals or animals that are under par and are convalescing in a first aid tank etc. The same also goes for liquid vitamins that can be added to their drinking water, however it should be noted that these degrade very fast and need changing on a daily basis to be of any worthwhile use. These preparations are best used for specific purposes and that they are probably unnecessary with healthy gerbils on a good diet. There are two types of vitamins, fat-soluble ones and water soluble ones. Excesses of fat-soluble vitamins can be dangerous because they are stored in fat cells in the body and it is easy to overdose with these. Water-soluble vitamins are safer but excesses of them are passed in the urine, so overdosing is a waste of money and hard on the kidneys.
Most animals lose the enzymes needed to digest milk after they have been weaned. Although humans are exceptions to this, several races from around the world where adults do not normally consume milk have more or less lost the ability to digest it. Lactose (milk sugar) intolerance is common in these races, and the consequence of not being able to digest milk properly can be very unpleasant. If milk, or milk products are given to gerbils, it should only be offered in very small amounts.
Yoghurt is fine in small amounts, especially those containing probiotics. Yoghurts should be plain and free from added sugars. Bacterial cultures used to produce yoghurts convert the majority of the lactose into simple sugars so are fine to use in small quantities. Probiotic yoghurts are especially good following a period of antibiotic use.
Eggs can be a valuable food source, especially for breeding pairs of gerbils. It's usually best to to boil the egg or buy in the form of egg biscuits or similar. Avoid the use of raw eggs. Raw egg white contains a protein called conalbumin which binds to iron. In addition to this it also contains a protein called avidin, which impairs the absorption of biotin (a B vitamin). A biotin deficiency can cause skin and hair coat problems (however saying this it would take a lot of raw eggs to get deficient in biotin) . Also depending on source there can be a potential risk of salmonella.
Cheese seems to be fine in very small quantities and as a rare treat. It is very nutritious providing energy, protein, vitamins , and minerals such as calcium, phosphorus and zinc. Bear in mind that most cheese is high in fat and cholesterol. Fat free cheese such as parmesan, or cheese made from low fat milk are almost cholesterol free. Cheese is fairly low in lactose, especially types like Cheddar, Colby, Parmesan, Swiss and Cottage cheese. This is due to the fact that most of the whey is removed (and with it the lactose) during the process of making cheese. In mature, ripened cheeses the lactose dissapears completely in around 3-4 weeks.