7766

• UCREFRP Catalog Number: 7766
• Author: Scholz, A. T., et al.
• Title: Notes on the Development and Measurement of Egg and Larval Thyroxine Concentration in Flannelmouth Suckers ‎(
• USFW Year: 1992.
• Copyright Material: NO

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3.0 RESULTS

3. 1 T4 Concentration During Development of Flannel Mouth
Suckers

Thyroxine concentrations were measured in a total of 540
flannelmouth sucker eggs and larvae. Eggs from the first group, fertilized
on 28 May 1991, began hatching between day 5 and 6 and completed
hatching on day 7 post-fertilization. Swim-up began on day 10 post-
fertilization. Weight loss occurred at the time of hatch (Fig. 1). Fish
started to gain weight by day 10 post-fertilization.

Mean T4 concentration (:t SEM) of eggs ranged from 1.7 :t 0.2 nglg
body weight to 4.2 :t: 0.8 nglg body weight for the first five days post
fertilization, and peaked at 18.6 nglg body weight at the time of hatch on
day 6 post-fertilization (Fig. 2). After declining to 5.9 :t 0.7 nglg body
weight on day 9 post-fertilization, T4 concentration peaked a second time
at 14.9 :t: 0.7 nglg body weight at the time of swim-up on day 10 post-
fertilization (Fig. 2).

Eggs from the second group, fertilized on 10 June 1991, started
hatching on day 6 and completed hatching on day 7 post-fertilization.
Swim-up occurred on day 9 and 10 post-fertilization. Weight loss
occurred at the time of hatch and individual started to gain weight on day
9 and 10 post-fertilization (Fig. 3).

Mean T4 concentration (:t SEM) of eggs ranged from 1.6 :t 0.4 nglg
body weight to 2.5 :t 0.4 nglg body weight for the first four days post
fertilization and peaked at 8.5 :t: 5.6 nglg body weight just prior to hatch
on day 5 post-fertilization (Fig 4). After decreasing between a range of
3.4 :t 0.2 nglg body weight to 4.1 :t 1.1 nglg body weight on days 7 to 9
post-fertlization, T4 concentration peaked a second time at 11.8 :t 5.4
nglg body weight, just before swim-up on day 9 post..fertilization (Fig. 4).
By day 24 to 38 post fertilization T4 concentration had decreased to 5.8 :t
0.2 and 5.1 :t: 1.4 nglg body weight respectively (Fig. 4).

3.2 Quality Assurance Results

Results of quality assurance samples are recorded in Table 1. The
actual concentration of the low concentration sample was 2.3 ngldl
compared to a mean (:t 95% CI) measured value of 2.1 :t 0.1 ngldl (n=6).
The actual concentration of the medium concentration sample was 7.3
ng/dl compared to a mean (:t 95% CI) measured value of 8.0 :t: 0.6 ng/dl

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