Management Guide 4: Trout Logic
Behind every shipment of Troutlodge eggs, we undertake a process that ensures we deliver only the best product in the industry. This process was...
Trout Logic Guide:
The Egg Journey -
Handling & Counting eggs
Part 4
The Egg Journey
Introducing Part 4
Introduction
Behind every shipment of Troutlodge eggs, we undertake a process that ensures we deliver only the best product in the industry. This process was developed and improved over the past 80 years, and is one of the reasons why Troutlodge remains the world leader in trout breeding. In our fourth edition of Trout Logic: The Egg Journey; Proper Egg Handling & Counting, we discuss pre and post arrival activities that set you up for success and counting egg methods for increased accuracy.
This management guide series covers the following topics:
Pre-arrival activities
This chapter provides the necessary technical guidelines to assist the producer in the management of the different critical points at the beginning of the production cycle for rainbow trout.
Egg handling:
Pre-arrival activities
Training the technical staff in charge
The human component is certainly a very important part of handling eggs properly. Hatchery staff with thorough technical training are able to take fast action to deal with any setbacks that may arise during the egg handling process.
Disinfection of materials, equipment, and installations.
Materials and equipment must be washed and disinfected before and after use in the reception of eggs. These disinfectants must be for aquaculture and environmentally friendly (quaternary ammonia or organic iodine). The manufacturer's instructions should be followed. These materials and surfaces must be well-rinsed before direct use on the eggs.
Monitoring water quality parameters
Water quality monitoring is very important throughout the trout production cycle, and this requires a lot of attention. It is key to know the times of the day and/or season when you have a better water quality, whether in temperature, dissolved oxygen, or other parameters. Monitoring can be done with simple equipment like thermometers or more complex equipment such as multiparameter devices. This will allow you to know how the water quality changes during the day and over the historical time frame of the farm.
Preparation of egg incubation units
Facilities should be checked in advance to ensure they are in optimal condition regardless if the hatchery is large industrial or small artisan. The important thing is that the system is sanitary and in proper operation. The flow of water should be as expected and without leakage of water or eggs. Incubators must have the appropriate dimensions that allow for proper management of the planned egg density, with optimal water flow and the possibility for adequate cleaning and extraction of waste.
Materials for receiving eggs:
- Fast and refrigerated transport
- Ice
- Von Bayer
- Graduated jar
- Iodine for eggs
- Thermometers
Transporting the eggs to the Hatchery
Once the eggs arrive in the importing city or country, they must be carefully reviewed by a representative of the importing company. Any irregularities in your receipt, as well as the time and conditions at which it was received, must be reported.
For transportation to the hatchery, the shipping boxes must be upright and in good condition. From receipt at the airport to arrival at the hatchery, the cargo should be the responsibility of the importer. Transport must occur in the shortest possible time in refrigerated trucks or containers to preserve the temperature of the eggs inside the shipping boxes.
The journey:
Arrival and Post-arrival activities
The eggs arrive after a long journey. Being ready to open the boxes and carry out the Re-incubation work as soon as possible is key to the success of our operation.
Egg handling: Arrival & Post-arrival activities
When the egg boxes arrive in the hatchery, boxes should be disinfected and treated with the utmost care, to avoid excessive handling of the product.
Customers should open egg boxes, preferably following the instructions below:
1. Remove tape, lid, and polystyrene.
2. Open the plastic bag and remove the ice.
3. Carefully cut the sides of the box, without cutting the trays.
4. Slide trays from box, supporting from bottom. Remove tape from trays and separate trays.
At this stage of the process you should observe and record the following:
- Box conditions upon arrival at the hatchery
- Arrival time and egg temperatures (average temperature per tray)
- Percentage of dead eggs, dehydrated-looking eggs or any other unusual conditions.
- Any other observations regarding boxes, trays, ice, or eggs.
These observations should be recorded and kept regardless of whether the shipment is in good condition or not. The information is invaluable in monitoring shipping success rates and any variation in those rates over time.
Rehydration and acclimatization
As determined by Troutlodge’s latest study you do not need to invest much time in temperature acclimatization but should rather focus on the hydration of the eggs on arrival at the hatchery. This is due to poor acclimatization practices that can suffocate eggs. This malpractice consists of placing the eggs for several hours in buckets of water without adequate water replacement. Eggs need a lot of oxygen after their long journey. However, if your hatchery has well-trained staff, the right facilities, sufficient water flow and backup oxygen, you may be able to safely acclimatize while hydrating the eggs. This ideal acclimatization should be performed by gradually increasing the temperature of the eggs to the temperature of the hatchery water (2C/hour). At the end of this, the eggs will also be completely rehydrated.
Best hatch rates are achieved by rehydrating, disinfecting if necessary and placing eggs directly into incubation as quickly as possible upon arrival.
Egg disinfection
To reduce the risks of introducing disease, re-hydrated eggs should be disinfected with any iodine-based aquaculture product for a period of 10 minutes at 100 ppm
Re-incubation of eggs
It is important to know the approximate number of eggs that are placed in each productive unit. To do this, use the methods for estimating the number of eggs that were described in this miniguide. Eggs should be kept away from direct light until the end of hatching. The monitoring of water quality parameters is essential at this stage, as it will determine the development and health of the new fingerlings. Eggs during re-incubation should not be subjected to any type of stress, except the minimum caused by cleaning procedures and some other treatment to prevent some type of fungus.
Visit our website to discover more about trout breeding and how we can help improve your trout breeding business.
Counting eggs
Once the eggs have been successfully re-hydrated, acclimatized, and disinfected, the counting should be carried out.
Counting eggs
Once the eggs have been successfully re-hydrated, acclimatized, and disinfected, the counting should be carried out. There are several methods of estimation of eggs, but the most recommended is the Von Bayer trough method, as it is quick, simple and utilizes a trout egg measuring trough, easily made but also available from Troutlodge on request. The trough measures 30.5cm (12") length (inside dimension), with a 45º bend and a depth of approximately 3.5cm (1.4").
On the following pages, Von Bayer estimation method can be found, including:
- First sizing the eggs
- Then counting the eggs
|
Number of Eggs per 12" Trough
|
Diameter of Eggs (Inches)
|
Diameter of Eggs (mm)
|
Number of Eggs per Liquid Quart
|
Number of Eggs per Liter
|
Number of Eggs per Liquid Ounce
|
|
35
|
0.343
|
8.712
|
1,677
|
1,772
|
52
|
|
36
|
0.333
|
8.458
|
1,833
|
1,937
|
57
|
|
37
|
0.324
|
8.230
|
1,990
|
2,103
|
62
|
|
38
|
0.316
|
8.026
|
2,145
|
2,267
|
67
|
|
39
|
0.308
|
7.823
|
2,316
|
2,448
|
72
|
|
40
|
0.300
|
7.620
|
2,606
|
2,754
|
81
|
|
41
|
0.292
|
7.417
|
2,690
|
2,843
|
84
|
|
42
|
0.286
|
7.264
|
2,893
|
3,057
|
90
|
|
43
|
0.279
|
7.087
|
3,116
|
3,293
|
97
|
|
44
|
0.273
|
6.934
|
3,326
|
3,515
|
104
|
|
45
|
0.267
|
6.782
|
3,556
|
3,758
|
111
|
|
46
|
0.261
|
6.629
|
3,806
|
4,022
|
119
|
|
47
|
0.255
|
6.477
|
4,081
|
4,313
|
128
|
|
48
|
0.250
|
6.350
|
4,331
|
4,577
|
135
|
|
49
|
0.245
|
6.223
|
4,603
|
4,864
|
144
|
|
50
|
0.240
|
6.096
|
4,895
|
5,173
|
153
|
|
51
|
0.235
|
5.969
|
5,214
|
5,510
|
163
|
|
52
|
0.231
|
5.867
|
5,490
|
5,802
|
172
|
|
53
|
0.226
|
5.740
|
5,862
|
6,195
|
183
|
|
54
|
0.222
|
5.639
|
6,185
|
6,536
|
193
|
|
55
|
0.218
|
5.537
|
6,531
|
6,902
|
204
|
|
56
|
0.214
|
5.436
|
6,905
|
7,297
|
216
|
|
57
|
0.211
|
5.359
|
7,204
|
7,613
|
225
|
|
58
|
0.207
|
5.258
|
7,630
|
8,063
|
238
|
|
59
|
0.203
|
5.156
|
8,089
|
8,548
|
253
|
|
60
|
0.200
|
5.080
|
8,459
|
8,939
|
264
|
|
61
|
0.197
|
5.004
|
8,851
|
9,354
|
277
|
|
62
|
0.194
|
4.928
|
9,268
|
9,794
|
290
|
|
63
|
0.191
|
4.851
|
9,712
|
10,264
|
304
|
|
64
|
0.188
|
4.775
|
10,184
|
10,762
|
318
|
|
65
|
0.185
|
4.699
|
10,638
|
11,242
|
332
|
|
66
|
0.182
|
4.623
|
11,225
|
11,863
|
351
|
|
67
|
0.179
|
4.547
|
11,799
|
12,469
|
369
|
|
68
|
0.177
|
4.496
|
12,203
|
12,896
|
381
|
|
69
|
0.174
|
4.420
|
12,846
|
13,574
|
401
|
|
70
|
0.171
|
4.343
|
13,533
|
14,302
|
423
|
|
71
|
0.169
|
4.293
|
14,020
|
14,816
|
438
|
|
72
|
0.167
|
4.242
|
14,529
|
15,354
|
454
|
|
73
|
0.164
|
4.166
|
15,341
|
16,212
|
479
|
|
74
|
0.162
|
4.115
|
15,916
|
16,820
|
497
|
|
75
|
0.160
|
4.064
|
16,621
|
17,565
|
519
|
|
76
|
0.158
|
4.013
|
17,157
|
18,132
|
536
|
|
77
|
0.156
|
3.962
|
17,825
|
18,837
|
557
|
|
78
|
0.154
|
3.912
|
18,528
|
19,580
|
579
|
|
79
|
0.152
|
3.861
|
19,270
|
20,365
|
602
|
Table 1. Von Bayer Chart for the estimation of the number of eggs
Sizing the eggs
- Eggs during transit can become dehydrated and slightly smaller in size so it is important to rehydrate the eggs in flowing water.
- Fill your Von Bayer trough with a single row of eggs.
- Use a non-sharp pointed object (pencil) to discard extra eggs from the trough. Do not force the eggs into the trough. The eggs should fit side-by-side, just touching, but there should not be any spaces.
- Count the number of eggs that fill the trough.
- Refer to the Von Bayer chart below, to determine the size of the eggs (eggs per litre or liquid ounce).
Counting the eggs
Other egg counting methods include:
Volumetric method
This consists of measuring 10 ml of eggs by water displacement, counting the number of eggs and repeating the procedure to get the average number of eggs in that 10 ml. Then multiply this number by 100 to calculate the number of eggs per liter. Next, determine the total volume of eggs. The final estimated number of eggs will be equal to the number of eggs calculated per liter multiplied by the total volume of eggs in liters. If you have trained staff available, you can do the same with 20 ml or more. This takes more time and handling but will give you a more accurate number.
Egg weighted using an egg counting pallet
In this method, eggs are individually placed on a tray with a specific number of egg-sized holes. This quantity of eggs is then weighed to get an average weight per egg. Finally, the total number of eggs is weighed and then divided by the average weight per egg to get an approximation of the total amount of eggs.
The general workflow would be:
- Place an empty egg tray on the scale.
- Tare the weight of the egg tray. We must make sure that the weight is now zero.
- Put a sample of eggs on the tray. The more the better.
- The eggs in the tray must be perfectly counted. It is ideal to use an egg counting pallet to ensure the accuracy of the counting.
- Take note of the total weight of the eggs in the sample.
- Return the eggs from the sample to the trays with the other eggs.
- Weigh and record the weight of all egg trays keeping the tared weight of the empty tray. This will throw out the weight of the eggs only and not the tray.
- Add the weight of all the eggs.
- Perform a simple rule of three to calculate the total number of eggs.
Finally, remember that this method is an estimate of the total number of eggs. That is, it is not exact, it is an approximation. For this reason, it is recommended to average the value of the estimate with the value of another estimate such as the Von Bayer method.
Counting Eggs- Q-sorter
In the past, Troutlodge has depended on volumetric measurements, such as the Von Bayer Method, to numerate eggs for both internal and external purposes. As with many of our operations, technology and modern manufacturing has brought forth new equipment to make methods more accurate and efficient. In 2016, Troutlodge incorporated the use of an automatic, counting and sorting machine for trout eggs: Q-sorter, as part of our egg processing and shipping operations.
Description:
- It processes eggs in a developmental stage of 200-250 degree days, and separates them based on three characteristics: viable, non-viable, and by size.
- In the process, the eggs are transported mechanically and hydraulically without suffering damage or stressful processes.
- In addition to classifying and counting, the Q-sorter can generate an accurate graph of size distribution for an entire lot of eggs.
- Q-sorter has the ability to sort eggs at a rate of 1,500,000 eggs per hour.
- Third party testing has confirmed the Q-sorter numeration to be accurate to 99.989%
Note: "Tamaño" means "Size"
Counting and Sorting- Maximum Accuracy and Reliability.
Counting eggs has to be not only gentle but accurate; we have that with the implemented technology based on computing vision. This technology ensures that no egg can “escape” the machine's "eyes". Every single egg is visualised by high definition cameras thanks to a sophisticated mechatronic device that holds and transports the embryonated eggs through the inspection zone. So, every single egg is identified, therefore counted and the data is sent to the sorting system, which is then able to separate the good eggs (eyed egg) from the bad eggs (non-embryonated or dead).
The operator visualizes at real time, at a speed of approx. 1.5M eggs/hr., how many eggs are being counted and so, the machine is able to stop when the desired quantity is reached (e.g.: 1.7M Eggs). The system has been engineered and manufactured in order to provide the highest level of reliability, accuracy, processing speed, and gentle manipulation of the eggs. The whole process of counting and sorting is totally automatized and a log is generated after every batch to ensure traceability. Even so, the counting is periodically tested in order to ensure a product totally free of counting error. We are proud to state that the technology in use is the most accurate and fast technology on the market.
Egg sampling
Another important activity that must be carried out is the sampling of the eggs.
Egg sampling
Another important activity that must be carried out is the sampling of the eggs. This is done to get an idea of survival after the incubation period, and thus, to be able to make a projection of the production for the next stages. The most common classifications in this sampling:
2. Infertile or empty eggs
6. Microphthalmia and Macroftalmia
