Thiamine allocation and deficiency status throughout the life cycle of cod

Several wild bird and fish species across the Northern Hemisphere have been shown to episodically be thiamine (vitamin B1) deficient, leading to mass-mortality events in offspring. To understand the mechanisms underlying thiamine deficiency, we need a better understanding of the dynamics and somatic allocation of the vitamin. Here, we focus on an ecologically and economically important species, i.e., Atlantic cod (Gadus morhua), which has been suggested to be sensitive to thiamine deficiency. We sampled cod of varying sizes and maturity stages in a system where thiamine deficiency regularly occurs (i.e. Baltic Sea) and compare these with cod from the North Atlantic, where deficiency has not been recorded. Results show that thiamine concentrations were tissue-specific. Concentrations in muscle and liver declined during growth and maturation, whereas concentrations in gonads increased. Of the total thiamine in a female’s body, approximately 70% was allocated to the gonads at the onset of ..., Study system & sampling
Cod specimens were sampled in the North Sea, Baltic Proper, and Åland Sea (Fig. 1A). In the North Sea, thiamine deficiency has never been observed, and while cod stocks are declining, cod still show good condition and grow to large sizes (Fig. 1B,C). This is also true for cod in the Åland Sea, whereas most other stocks in the Baltic Sea, including the Baltic Proper, have shown rapid declines, low condition factors, and size truncation. Hence, we used the North Sea and Åland Sea stocks as reference points to compare them to the Baltic Proper stock, which is suffering from the aforementioned symptoms and a suggested thiamine deficiency. Through coalescing the data on thiamine from all three stocks, we seek to better understand the extent of the potential thiamine deficiency as well as the general thiamine dynamics throughout cod development and reproduction.
All sampled cod individuals were caught as part of environmental monitoring programs conducted by the Sw..., # Thiamine allocation and deficiency status throughout the life cycle of cod

Dataset DOI: [10.5061/dryad.cjsxksnjc](10.5061/dryad.cjsxksnjc)

## Description of the data and file structure

We investigated the thiamine status of Atlantic cod of the North Sea, Baltic Proper and Åland Sea to better understand the prevalence of thiamine deficiency in these stocks and how thiamine is allocated throughout the life cycle of cod. Thiamine diphosphate, thiamine monophosphate, and free thiamine concentrations were measured in muscle, liver, and gonad tissues. The activity and latency of transketolase in liver was measured in a subset of specimens. For more details, see attached methods section or publication.

### Files and variables

#### File: tbl_Fish.csv

**Description:** Table containing general information about each specimen

##### Variables

* fish_UID: (char) main UID for each fish
* fish_UIDSVEA: (int) system-specific UID used in database on RV SVEA
* fish_UIDOTOLITH: (int) otolith nu...,