It does not always need to be antibiotics: healthy pig breeding

Scientists found a way to reduce the application of antibiotics in pig breeding by using antimicrobial peptides. The results of the study have just been published in the scientific online-journal PLOS ONE.

Researchers investigated the application of antimicrobial peptides (AMP) as substitutes for antibiotics in liquid sperm preservation. Firstly they were able to show that AMPs fight bacteria effectively in test tubes. Then they showed that two of the investigated AMPs suppressed bacterial growth in liquid preserved semen preparations if combined with a small amount of the antibiotic "gentamicin." The sperm quality was not impeded by this addition.

Bacteria are extremely adaptable which can lead to an increasing resistance against antibiotics. This causes big problems for breeders when using artificial insemination, the method most commonly used in assisted reproductive technology in pig production worldwide. Freshly retrieved boar ejaculates always contain bacteria. These germs are detrimental to the quality as well as the longevity of liquid preserved sperm, with dire, negative consequences for fertility. The addition of antibiotics to liquid semen is required by law and facilitates an inhibition of bacterial growth. However, many types of bacteria quickly develop resistances to the usually applied antibiotics. Hence it is important to look for new antimicrobial alternatives.

Scientists from the German Leibniz Institute for Zoo and Wildlife Research (IZW) investigated the effect of antimicrobial peptides in cooperation with the Leibniz Institute of Molecular Pharmacology (FMP) and the Institute for Reproduction of Farm Animals Schoenow e.V. (IFN). These molecules are naturally occurring amino acid compounds, are toxic for bacteria and can be found in nearly all organisms as a first defence against germs. For this study, synthetic cationic antimicrobial peptides were produced. "Antimicrobial peptides do not offer a complete alternative for traditional antibiotics in liquid sperm preservation, but allow a substantial reduction in their concentration," explains Dr Karin Müller from the IZW. "This is a benefit for people as well, as the occurrence of resistance will be reduced if fewer antibiotics are used."

Additional application possibilities are conceivable, outlines Dr Margitta Dathe from the FMP. "Antimicrobial peptides could be used for the preservation of other cells as well. Furthermore special AMPs for the treatment of superficial infections could be developed."

Story Source:

The above story is based on materials provided by Forschungsverbund Berlin e.V. (FVB) . Note: Materials may be edited for content and length.

City life makes bigger spiders [Life Lines]

A new study from researchers at the University of Sydney shows that golden orb-weaving spiders (Nephila plumipes) that live in the city are larger and produce more offspring as compared to country living.

When they say the spiders are big, they mean really big. The females can reach up to 20-25mm (males are only ~5mm).

Image from Spiders of Australia

http://ift.tt/1prTboW

The researchers speculate that the urban heat island effect, which is attributed to a lack vegetation and hard surfaces, may lead to the increased body size as invertebrates in warmer climates tend to be larger. Further, they speculate that the abundance of insects attracted to urban lighting (i.e. spider food) also promotes growth and reproductive success.

Sources:

Lowe EC, Wilder SM, Hochuli DF. Urbanisation at Multiple Scales Is Associated with Larger Size and Higher Fecundity of an Orb-Weaving Spider. PLoS ONE 9(8): e105480. doi:10.1371/journal.pone.0105480

University of Sydney press release

Crayfish Gastroliths [Aardvarchaeology]

It’s the time of the year when it used to become legal to catch and sell Swedish crayfish, and so the grocery stores sell Turkish and Chinese crayfish for a few weeks. The traditional way to eat them is to boil them with dill, salt and a little sugar, and serve them with toast, strong cheese, beer and akvavit. I don’t drink but I love shellfish, so crayfish time is always a treat for me. My wife, being refreshingly unorthodox about traditional Swedish customs, and indeed about all traditional customs thanks to a Maoist childhood, served crayfish with smoked shrimp, aïoli and boiled potatoes last night.

There’s a fun detail about these animals: sometimes you find a pair of little white buttons in their heads. These are known as kräftstenar in Swedish, “crayfish stones”, and gastroliths in English. (The same word is also used for actual stones eaten by crocodiles, birds and other dinosaurs to help digest their food.) As Andrew Hosie of the Western Australian Museum explains:

… crayfish gastroliths … represent a remarkable physiological process to conserve calcium.

Much like people require calcium for strong and healthy bones, so too does a freshwater crayfish to maintain its armour. … As crayfish (indeed all crustaceans) grow bigger, they must periodically shed the exoskeleton and form a new one. To start a new exoskeleton from scratch would require large amounts of new calcium.

The hormones that drive moulting (referred to as ecdysis) trigger calcium carbonate to be removed from the exoskeleton and starts forming a pair of these gastroliths in the stomach. After the crayfish has moulted, the gastroliths are reabsorbed and used in the strengthening of the new exoskeleton. Only freshwater crustaceans form gastroliths because unlike seawater, freshwater has very little dissolved calcium salts, so in an effort to retain calcium, crayfish form these little gastroliths, or even eat the old exoskeleton.