CC BY
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4. Бондарев, В. А. Приемы повышения качества кормов / В.А. Бондарев // Кормопроизводство. 1997. №4. С. 33-37.
5. Лаптев, Г. Биотроф-600 - альтернатива химическим консервантам / Г.Лаптев,
B. Солдатова// Агрорынок. 2005. №7. С.33-34.
6. Панов, А.А. Силосование кормов с биологическими препаратами /А.А. Панов// Кормопроизводство. 1996. № 2. С. 36-38.
7. Победнов, Ю.А. Оценка эффективности препаратов молочнокислых бактерий при силосовании трав / Ю.А. Победнов // Кормопроизводство. 1999. №5. С. 28-32.
8. Попков, Н.А. Качество силоса из зеленой массы кукурузы, консервированного бактериальной закваской и эффективность его использования при откорме молодняка КРС / Н.А. Попков // Пути увеличения производства молока и говядины. Горки, 1987.
C. 89-90.
9. Рекомендации по применению бактериальной закваски для силосования кормов // РАСХН; ВНИИСМ. СПб.: 2000. 20 с.
УДК 636.086.53
FIN DAMAGE-PROBLEMS OF FARMED SALMON (SALMO SALAR) IN LATVIA
R. MEDNE, E. LIEPINS Latvia Univerity of Agriculture, Faculty of Veterinary Medicine M. ZINGIS
Institute of Food Safety, Animal Health and Environment «BIOR»
(Поступила в редакцию 10.01.2011)
Introduction. There are increasing interests in the welfare of farmed fish. There are many discussions about what welfare means and how it has been assessed. Dawkins (2004) suggested to simplify welfares in two questions: Are the animal healthy? Do they have what they need?
Widely distributed problem on fish farms is fin necrosis. The fin necrosis is a shortening of the fin length due to damage of the fin tissue. The best-know fin damage is termed fin necrosis, fin erosion or fin rot. The fin rot disease occurs as an acute or chronic degenerative condition of freshwater, marine and anadromous fishes (Schneider et al., 1980). Fin necrosis starts at the edge of the fins, and destroys more and more tissue until it reaches the fin base. If it does reach the fin base, the fish will never be able to regenerate the lost tissue. In such fish, damage or loss of the fins affects their swimming ability (Alejev, 1963) consequently, their capacity to capture prey and avoid predation (Nicola and Cordone, 1973) and accordingly affect fish welfare (Ellis et al., 2004).
Higher fish densities (Ellis et al., 2004) and poor water quality (Wiklund et al. 1995) were associated with increased fin erosion. Fin necrosis can be the result of a bacterial infection, or a fungal infection. Sometimes, both types of infection are seen together. Infection is commonly brought on by bad water conditions, injury, poor diet (Ellis et al., 2004).
There are a lot of bacteria found in fresh water aquatic environments. Some of them are initiate morbidity of aquatic animals. Bacteria from Genus Aeromonas may initiate common septicaemia in fish. Motile and non-
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motile aeromonads are caustative for fish (Stoskopf, 1993). Aeromonas infection does not follow strict temperature ranges and has been reported during every month of the year (Camus et al., 1998).
The aim of investigation - to make clinical characterisation of fin erosion and to determine the bacteria associated with the disease.
Materials and methods. Baltic salmon parr's from fry to smolts were examined around the year. The fish in hatcheries were kept in 800 L tanks and supplied with aerated fresh water. Fish were fed daily on a pelleted diet of an appropriate size according to manufacturer's tables. Feed was dispensed from clockwork belt feeders in the circular tanks. For clinical investigation and bacteriology we acquired fish on hatcheries.
For artificial infection we acquired fish one month after first-feeding. Experimental fish were kept in 100 L tanks and supplied with aerated fresh water. Temperature of water was 19-20 °C. The fish were fed manually by commercial feed pellets of an appropriate size and amount.
Clinical examination was made on hatcheries, in Latvia Fisheries Research Institute and Latvia Fish Research Agency.
Fins were examined and stage of fin necrosis scored (D) using the system adapted from that outlined by Carter et al. (1994): D0- no damage, D1-less 30% of fin missing, D2- from 30 to 70% of fin missing, D3 more than 70% of fin missing.
Progression phase was divided into four groups: 0- health fin, 1- acute progressive process, 2- start of healing (healing fin), 3- healed fin.
Bacteriology was made in Latvia Fisheries Research Institute and Veterinary Medicine Diagnostic Centre (now named Institute of Food Safety, Animal Health and Environment „BIOR").
The fish were placed on the ice and immediately transported to the laboratory for further analyses. Samples collected from fins, bacteria were cultured on nutrient agar. All plates were cultured at 18-20°C for 24-72 h, and representative colonies were reisolated for characterization and identification according to standard bacterial methods.
Determination of Aeromonas virulence. Bacteria for infection were cultivated on special plates at 18-20 °C for 24 h afterwards bacteria were counted by Standard. Before handling for fish were used anaesthetic. There are different infection methods we used: first method -fish were dipped in bacteria suspension, second method- were made incision in dorsal fin by scissors, after them fish were dipped in bacteria suspension. For infection were used A. salmonicidae and A. hydrophila.
In total there are four experimental and two control groups: 14 fish in each group. Fish were observing twice a day. Fin of death fish were asepti-caly took for bacteriology.
Statistics. All data analyses were performed using the statistical methods (Arhipova I., Balina S. 2000). The fin necrosis index was calculated by,
3
I^N^nA
n=0
Were n- number of fish with same score of necrosis (or progresion phase) severity (0-3), N- total number of fish in group.
Results and discussion. Fin necrosis is acute or chronic degenerative condition of many fish species. Undamaged fins revealed a smooth distal edge, the surface of the fin is steady, fin rays are intact. The acute state of fin necrosis is chacterized by a progressive destruction of fin tissue. A lot of necrotic tissue located on the periphery of fin. In some cases fin rays to fall out and developed ulcers, that may be 2-2,5 cm long and deep i.e. 10% of fish lengths. The acute state of fin necrosis is chacterized by a progressive destruction of fin tissue.
Necrosis of dorsal fin in salmon parr age from fry to smolt was observed in 95,0 % of the case (Fig.1).
Fig.1. Frequency of fin damage
Pectoral fin necrosis was observed in 51,0 % of cases, ventral and anal fin necrosis was observed more rarely.
Highest index of fin necrosis was in dorsal fin in parr and smolt groups. Caudal and dorsal fin are more affected in fingerlings (fig. 2).
Fingerlings ■ Parr Smolt
Dorsa Rectora Ventral
Ana
Fig. 2. Index of fin necrosis 40
Index of dorsal fin necrosis was not significant (P>0,05) different between parr and smolt groups. The fingerlings (0+) significant (P<0,05) less frequently affected by the dorsal fin necrosis, than parr (1) and smolt. Interaction of the pectoral fin necrosis is very significant (P<0,05) between fingerlings and smolt. The salmon fingerlings (0+) are less frequently affected by the pectoral fin necrosis, than the parr (1) and smolt. Interaction of the caudal fin necrosis is very significant (P<0,05) between fingerlings and parr. In the smolt isn't observed caudal fin necrosis.
Fingerlings are small fish in its first summer. Water temperature in summer is good for bacteria, therefore in fingerlings was highest number of acute fin necrosis. In the autumn fingerlings become parr, temperature of water decrease, and fin wounds and ulcers start healing. The lots of affected fingerling and parr died. The acute necrosis in smolt (in spring) was in some cases only (tab. 1).
Table 1. Fin necrosis progression phase in salmon (%)
Fish Progression phase Fin (%)
Dorsal Pectoral Ventral Anal Caudal
Fingerlings Health 6,3 68,8 95,3 81,3 62,5
Acute necrosis 62,5 14,1 - - 6,3
Healing 28,1 9,4 - 6,3 9,4
Healed 3,1 7,8 4,7 12,5 21,9
Parr Health 5,1 53,9 98,7 100,0 94,9
Acute necrosis 10,3 2,6 - - -
Healing 25,7 9,0 - - -
Healed 59,0 34,6 1,3 - 5,1
Smolt Health - 70,7 98,3 100,0 100,0
Acute necrosis - 3,5 - - -
Healing 27,6 6,9 - - -
Healed 72,4 19,0 1,7 - -
The symptom was not observed.
Acute fin erosion, i.e. complete or partial loss of the distal part of the fin affected the fins of pikeperch. All fins were affected by acute fin erosion, but the caudal fin was most frequently affected (Wiklund et al. 1995). In our investigation, the most frequently affected was dorsal fin.
There is no relationship between the stage and progression phase of fin necrosis. Process of development of fin necrosis may stop in anyone stage of necrosis (tab. 2).
Table 2. Relationship of stage and progression phase of fin necrosis (% of case)
Fin Health Acute necrosis Healing Healed
D0 4,2 - - -
D1 - 8,2 12,3 25,0
D2 - 2,1 5,4 10,5
D3 - 9,7 7,2 15,4
Impossible combination.
Bacteriological analyses were made around the year. Aeromonas hydro-phila prevalence was high 67%, compared with A. salmonicidae (33%).
Microbial infection cause great losses in production and industry of fish. Tail and fin rot disease in fish is incriminated in outbreaks of bacterial hae-morragic septicaemia (Plumb, 1994). In our investigation were isolated grampositive and gramnegative bacteria.
To exist positive linear correlation (P<0,05) between fin necrosis progression phase and number of gramnegative bacteria. In fin necrosis progression phase 1, number of bacteria is the highest.
Assesment of Aeromonas virulence were made in Latvian Fisheries Research institute. After artificial infection part of fish died and we have made bacteriological analyses.
Cumulative mortality in both control groups was 21,4 % in group C1 and 35.7% in group C2, whereas in experimental groups all fish had died (Fig 3).
60 40 20 -0
-A. salmonicida A. salmonicida incision A. hydrophila A. hydrophila incision C1
- C2 (incision)
1 5 10 15 20 25 30 35 40
Fig.3. Cumulative mortality of artificially infected parr.
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All fish in experimental groups had died in different time. More susceptible fish was A. salmonicidae. Symptom of fin necroses were observed only in groups where was made incision. In all cases where the symptom was found we found bacteria used for artifical infection.
Motile aeromonads are among the most abundant bacteria found in fresh water aquatic environments. There are capable of producing disease in fish (Camus et.al, 1998). Aeromonas hydrophila was produced fin necrosis in our experiment, only after incision of fin.
Conclusion. Fin necrosis in most of cases affect dorsal fin. There is no correlation between stage and progression phase of fin necrosis. A.salmonicida and A.hydrophila can initiate fin necrosis after fin injury.
REFERENCES
1. Arhipova, I. Statistika ar Microsoft Excel ikvienam /I. Arhipova, S. Balina // I, II da|a Datorzimbu centrs, 2000. 123 lpp.
2. Camus, A.C. Aeromonas bacterial infections-Motile Aeromonad septicaemia / A.C. Camus, R.M. Durborow, W.G. Hemstreet, R.L. Thyne, J.P. Hawke // SRAC Publication 1998. P. 478.
3. Dawkins, M.S. Using behaviour to assess animal welfare. Animal Welfare / M.S. Dawkins // 2004., 13: S. 3-7.
4. Ellis, T. Stoking density and rainbow trout welfare: what does literature tell as? / T. Ellis, A. Scott // Trout News. 2004. 38 pp.10-13.
5. Nicola, S.J. Effect of fin removal on survival and growth of rainbow trout (Salmo gairdneri) in a natural environment / S.J. Nicola, A.J. Cordone // Tr.Am.Fish.Soc. 1973. 102, 753-758.
6. Plumb, A.J. Health maintenance of cultured fish principal microbial disease CRC press, Inc / A.J. Plumb // London, 1994.
7. Schneider, R. Bacteria associated with fin rot disease in hatchery-reared Atlantic salmon (Salmo salar) / R. Schneider, B.L. Nicholson // Can.J.Fisheries and Aquatic sc. 1980. 37, 1505-1513.
8. Stoskopf, M.K. Fish medicine / M.K. Stoskopf // In: Fish medicine. W B Saunders Company, London, 1993. P. 880.
9. Wiklund, T. Fin abnormalities of pikeperch in coastal areas off the Finnish south coast / T.Wiklund, G.Bylund // Journal of Fish Biology. 1995. 48, 652-657.
10. Алеев, Ю. Г. Функциональные основы внешнего строения рыбы / Ю.Г. Алеев // Москва: изд.-во академии наук СССР. 1963. 246 с.
УДК 637.125
ЭФФЕКТИВНОСТЬ КОРМЛЕНИЯ ДОЙНЫХ КОРОВ ЭКСТРУЗИОННО ОБРАБОТАННЫМИ ЗЕРНОВЫМИ
А.А. ТРУПА
Латвийский сельскохозяйственный университет, Агробиотехнологический институт г. Елгава, Республика Латвия, 3001 А.Я.СИЛИНЯ Акционерное общество "Tukuma Straume" Тукумский район, Тумская волость, Республика Латвия, 3139 Э.А. КРЕЙТУЗИС _ Крестьянское хозяйство "Udri" Лимбажский район, Пальская волость, Республика Латвия, 4052
(Поступила в редакцию 10.01.2011)
Введение. В процессе экструдирования, под влиянием высокой температуры (140-1500 C) и давления (4-4,5 атм.) происходят существенные физические и химические изменения в структуре крахмала зерновых - крахмал распадается на сахара. Наряду с этим крахмал легче усваивается и полностью используется в организме животного [3-5, 8]. В процессе экструдирования в определенной степени происходит санитария корма - под влиянием высокой температуры погибают колонии плесневых грибов, а также уменьшается всхожесть семян сорняков [1, 2]. К сожалению, в Латвии экструдирование корма - прогрессивный метод подготовки корма, практически не используют.
Экструдирование зерновых и кормление животных экструзионно обработанными зерновыми в крестьянских хозяйствах предоставило
