NLS for stingrays

[skynoch]

You can also achieve this growth rate without any pellets in your rays diet. I have rays that eat exclusively pellets and some are almost exclusively shrimp and some that are both.

No argument there, my point was simply that you don't have to supplement with fresh/frozen in order to achieve good solid growth, especially if the fish is already taking pellets, which these apparently are.

I'm also not so naive as to think that feeding nothing but pellets is the definitive answer to the best way to keep every fish thriving in captivity, but I do believe that whenever possible pellets should be an integral part of every fishes diet. (whatever brand one chooses)

I would also caution against feeding any fish a diet that mostly consists of shrimp. By feeding large amounts of shrimp you restrict the overall amino acid (protein) content of your fishes diet, along with various essential vitamins & minerals. Shrimp/market prawns are also known to contain thiaminase and when ingested in large quantities can destroy the natural thiamin (vitamin B1) which in turn can cause vitamin deficiency. You can read more about that in the following link.

http://albertaaquatica.com/index.php?showtopic=23186

Very good read thanks for the information. I'm still trying to find some information on the percentage of thiaminase found in different meaty foods we feed. If you have a link to this it would be very helpful.

I'm not trying to argue anything you said just trying to let people know there are alternative diets to pellets. The reason for this is I've had some rays that have had problems digesting pellets properly. Some were constipated and some had the same problem as letsgofishing. I know you've stated that in letsgofishings case it was fed too much. In a single ray tank this is easy to maintian, in a multiple ray tank it's not so easy. Other reasons may be the type of ray you are keeping. Some rays would sooner starve than take a pellet or a shrimp.

If thiaminase is a worry for some then it's best to feed cooked shrimp. Now some people are gonna say cooking your foods will cause you to lose to many nutrients. I've read reports on the cooking of shrimp and what is cooked out is not enough to concern yourself in the longrun. I've also heard the oppisite but have not seen any facts (I'm sure there out there so if anyone as a link great).

In all the more things you can get your ray to eat the better it will be.

[RD.]

I know you've stated that in letsgofishings case it was fed too much.

While that may possibly be the case (I obviously have no idea?), that's not exactly what I stated.

I said; "Be careful as to the quantity that you feed at one time, NLS pellets especially are a very nutrient dense food."

Many people in this hobby tend to overfeed, and gastrointestinal issues can certainly be the end result if one is overfeeding a nutrient dense food. I just wanted to make sure that this was clearly understood. I also understand that this may be easier said than done in a tank with multiple rays, and the same could be said about numerous other set ups, and thousands of other various species of fish. I guess sometimes that's the end result when we play God in a glass cage.

As far as thiaminase levels, I have no idea what the exact percentage is in shrimp, and of course that could vary greatly depending on the source of the shrimp. I'm certainly not against anyone feeding their rays seafood/worms etc, I just think that there are safer/better alternatives than shrimp, such as some of the foods listed in the following article.

http://www.wetwebmedia.com/ca/volume_6/vol.../thiaminase.htm

Edited June 28, 2009 by RD.

[skynoch]

Sorry didn't mean to miss quote ya

There is better sources to feed your rays for sure but availability and cost are a problem for some.

I apprciate the link to the thiaminase thread. I knew there was some in raw shrimp but would love to know the levels. If you ever come across this it would make a good post.

I agree our glasscages are not optimal but we try. :thumbs:

[RD.]

Finding percentages of thiaminase doesn't appear to be overly easy, but I did find an additional list of fish species that contain this substance. I'll add a caveat that I believe the thiaminase levels in some of the species in the list below are very low, or in fact may not even be present depending on the source of the fish. The info posted below from the U.S. Dept. of Commerce, pretty much confirms my suspicions. See below ....

And while it's true that heating will reduce thiaminase activity in raw fish, freezing does the opposite.

Freezing raw fish actually increases thiaminase levels.

Either way it's probably best to avoid species that are known to contain this anti-nutritional factor.

Occurrence of Thiaminase in

Some Common Aquatic Animals

of the United States and Canada

1971

SPECIAL SCIENTIFIC REPORT-FISHERIES Na 631

UNITED STATES DEPARTMENT OF COMMERCE

Maurice H. Stans, Secretary

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION

Dr. Robert M. White, Administrator

NATIONAL MARINE FISHERIES SERVICE

Philip M. Roedel, Director

Occurrence of Thiaminase in

Some Common Aquatic Animals of

the United States and Canada

By

R. A. GREIG and R. H. GNAEDINGER

Special Scientific Report — Fisheries No. 631

Seattle, Washington

July 1971

CONTENTS

Page

Introduction 1

Explanation of the tables 2

Discussion 2

Literature cited 3

TABLES

1. Thiaminase presence in freshwater animals 4

2. Thiaminase presence in marine animals 6

in

Occurrence of Thiaminase in Some Common Aquatic Animals

of the United States and Canada

By

R. A. GREIG

National Marine Fisheries Service

Technological Laboratory, Ann Arbor, Michigan 48107

and

R. H. GNAEDINGER

Pet Food Nutritional Research, Ralston-Purina Company,

Checkerboard Square, St. Louis, Missouri 63199

ABSTRACT

Two tables are presented that survey the presence or absence of thiaminase in

freshwater and marine fish and shellfish.

INTRODUCTION

The presence of thiaminase in fish that are

routinely used raw in rations for animals can

cause a dietary deficiency. The disease in mink

is commonly called Chastek paralysis (Green,

Evans, and Carlson, 1937). Knowledge about

the presence or absence of thiaminase in aquatic

animals is therefore important to mink ranch-

ers and other animal feeders, scientific re-

searchers, commercial fish vendors, and others.

Thiaminase is an enzyme that destroys

thiamine (vitamin Bi) and, like many enzymes,

its activity is greatly reduced or destroyed up-

on heating to moderate temperatures (50°-

100° C). Thus, mink ranchers, for example,

can cook the fish before feeding it to the animals

to avoid a Chastek paralysis problem (Lee,

1948; Gnaedinger and Krzeczkowski, 1966).

However, mink ranchers generally prefer to

avoid cooking the fish because mink show a

preference for raw fish and cooking adds to

the operational costs. Knowledge whether fish

do or do not contain thiaminase is therefore

vitally important to animal feeders, particu-

larly mink ranchers, for safety and economic

reasons.

Also, scientific researchers at times need to

consider whether or not an aquatic animal

involved in their research contains thiaminase.

For example, in biological research where

fishes are held in aquaria for feeding studies

or other research, the presence of thiaminase

in the animals being fed to the fish could pos-

sibly cause a vitamin deficiency or other prob-

lems that could impede the research (Wolf,

1942).

Many species of aquatic organisms have been

assayed for thiaminase activity in various lab-

oratories throughout the world. Most of these

assays, however, were made in conjunction

with specific research programs that were de-

signed to study a particular species native to

the area of the research laboratory. As a re-

sult, the data on the occurrence of thiaminase

in aquatic specimens is scattered throughout

various research papers published over the

years.

Deutsch and Hasler (1943) and Neilands

(1947) determined the thiaminase activity of

a great number of freshwater and aquatic an-

imals. A number of important fishes and shell-

fish, however, were not examined by these

researchers but were investigated by several

other researchers. The purpose of this report,

therefore, is to combine the listings of thiami-

nase activity in aquatic animals that have ap-

peared in the literature and also some recent

unpublished work at this laboratory into a

comprehensive list of aquatic animals that have

been assayed for thiaminase activity.

Explanation of the Tables

The list is presented in two tables: Table 1

presents the information for freshwater ani-

mals, and Table 2 presents the information for

marine animals. The animals are listed alpha-

betically by common name. The scientific name

is also shown for each animal; the names were

taken from the publication (s) cited. The sci-

entific names relating to the unpublished data

of this laboratory are from the list published

by the American Fisheries Society (1960).

The part of the animal that was analyzed

for thiaminase is also shown in the tables.

Whether the whole animal or, for example, just

the viscera was analyzed is important; this

point will be further discussed later. Where

the source of the animal was given in the ori-

ginal reference, this information is also given

in the tables.

DISCUSSION

In most cases, the whole animal was analyzed

for the data presented in Tables 1 and 2. How-

ever, for some of the animals, only the viscera

or flesh was analyzed. Thiaminase apparently

concentrates in the viscera more than in any

other part of the animal (Lee, 1948). Some

researchers have found thiaminase to be pi-esent

in the viscera of some aquatic animals but not

in the flesh of that same animal. For example,

Neilands (1947) found that viscera of lobster

contained thiaminase, but the muscle did not.

In over 30 marine and freshwater animals

studied by Neilands, however, the lobster

proved the only example of such a relationship.

In other experiments by Neilands (1947) and

by Stout, Oldfield, and Adair (1963), the ob-

servation was made that fish (yellow perch,

white perch, and hake in these experiments)

generally considered to be thiaminase-free

could be found to contain thiaminase activity

if the fish was captured at a time when the

animal it fed on was not completely digested

and this animal itself contained thiaminase.

These findings are significant for several

reasons: (1) It is possible that some of the

animals listed in Tables 1 and 2 were found to

contain thiaminase because they were caught

at a time when their stomachs contained un-

digested, thiaminase-containing feed. Also, the

opposite could be true; that is, those species

listed as not containing thiaminase could at

times be found to contain thiaminase activity

if captured with the undigested thiaminase-

containing food in their stomachs. (2) The

findings could help to explain apparent dis-

crepancies that sometimes occur in regard to

the reported thiaminase activity of a certain

species. For example, burbot is listed in Table

1 as containing thiaminase when the animal

came from the Great Lakes; whereas, burbot

did not contain thiaminase when captured from

Rainy Lake, Minn. It is possible that the bur-

bot feeds on thiaminase-containing animals in

the Great Lakes; whereas, the animals avail-

able for food in Rainy Lake are thiaminase-

free. Another possibility is that the burbot

from the Great Lakes was captured with un-

digested (thiaminase-containing) food in its

viscera, and the burbot from Rainy Lake was

captured with completely digested food in its

viscera.

Additional precautions that have to be con-

sidered in using the data presented in the tables

are: The data do not indicate which animals

have the greatest concentration of thiaminase

and which have lesser concentrations of the

enzyme. In many respects this factor may not

be too important, at least with present lack

of knowledge about threshold concentrations

in regard to the ability of thiaminase to impair

physiological activity of thiamine. In other

words, even a small amount of thiaminase in

the animal could cause concern depending on

the intended use of the animal. Thus, a mink

rancher is not likely to feed raw, thiaminase-

containing fish to mink even though it was

shown that the fish contained a relatively low

level of thiaminase activity. In this case, the

mink rancher would cook the fish to be on the

safe side. According to the results of research

by Gnaedinger and Krzeczkowski ( 1966) , it ap-

pears that fish with various concentrations of

thiaminase activity all have to be heated to

about the same temperature time relationship

to give complete destruction of thiaminase ac-

tivity. Therefore, a mink rancher probably

should not give fish with "low" levels of thi-

aminase a milder heat treatment than fish with

"high" levels of thiaminase.

Different analytic methods were used by the

various researchers to obtain the data pre-

sented in the tables. That is, the presence or

absence of thiaminase was observed through

various chemical methodologies or biological

feeding studies; it is possible that one method

of detection could show the presence of thi-

aminase, whereas another method would show

that the thiaminase was absent in the animal.

Generally, the chemical methods for thiaminase

activity are believed capable of detecting low-

er levels of thiaminase than the biological

methods.

HTH

[skynoch]

lol this was the only other info I could find last night while googling around. You would think with something that could prove very harmful (or not) there would have been more references to it.

Thanks for posting the information.

[RD.]

Unless it deals with fish raised for human consumption, no one seems to be willing to spend the time or $$ for in depth long term feed trials. (or even short term for that matter) When it comes to ornamental species, much is still unknown, so all one can really do is extrapolate the known info that is out there, and modify where need be. While this isn't overly difficult to do with regards to amino acids, lipids, carbs, and vitamins & trace minerals, it becomes rather difficult when subjects such as this rear their head.

With regards to thiaminase, I think that all one can really do is either avoid these foods altogether, or make sure that along with these foods one feeds a high quality pellet to counter any potential vitamin loss from the fresh/fozen foods. You can also add liquid vitamins to the food, but a lot of that will be lost to the aquarium water, so even that becomes somewhat hit & miss.

If nothing else I guess this helps answer Turtlechicks question. lol

[turtlechick]

UUUUMMMMMMM.....thanks for the response guys!!!! LMAO Got a little reading to do apparently. I ordered some of the NLS wafers from Nature's Corner Store. Just a small container for now to see what happens. This, along with shrimp and worms I hope will be okay. I wanna make sure I'm doing everything right.

PS....first water change today............there's gotta be an easier way............UUUUGGGGHHHHH.

[skynoch]

lol I'm sure your doing everything fine. RD is a very well informed guy and it' great to read his posts.

As far as waterchanges go you can get a python for emptying and cleaning the bottom and refilling if your using prime and tap water.

And if you use aged water you can use a python for draining and cleaning the bottom and a transfer pump for refilling.

The hardest thing with ray keeping is keeping up with the waterchanges. Good Luck.

[TylerG]

I was reading through this post the other night and thought that I would buy some and give it a try. I plunked a few of them around the tank and the rays went right for them. The only problem is that they did not eat them...

They moved them to the one corner of the tank but did not eat them. Any recommendations for convincing them to eat them?

Tyler

[dunl]

Starve them a bit. When they're hungry, they'll eat.