Values Of Growth Coefficient Research Articles

Fishery characteristics, population dynamics and the impacts of the invasive red swamp crayfish (Procambarus clarkii) in the Nile River, Egypt

Alien intrusive species are one of the extreme pressures on biodiversity for their rapid reproduction and adaptation to new environments. Crayfish Procambarus clarkii entered Egyptian freshwater ecosystems at the beginning of 1980's. After many years of negative effects of its introduction onto the Egyptian waters, it became one of the commercially important species. Population parameters of P. clarkii are estimated based on 1355 specimens collected from the Nile off El-Minya during 2019–2020. The isometric growth of the species under the study is confirmed according to the obtained b-value of length–weight relationship (LWR). Annual sex ratio (female : male) was in favour of females with an annual sex ratio 1.44 : 1. The values of growth coefficient (K) and the asymptotic total length (L∞) were assessed for males, females and combined sexes. Using mortality estimates, the exploitation ratio was 0.64 year–1. Investigation of relative yield per recruit (Y'/R) and analysis of relative biomass per recruit (B'/R) for P. clarkii in the Nile off El-Minya provides the highest (Y'/R) at Emax = 0.81 and the E0.5 (utilisation level that preserves the spawner stock biomass at 50% of the virgin spawning biomass) was 0.38. From fisheries management point of view, the current exploitation level should be decreased to that maintain the spawning stock biomass (from 0.64 to 0.38).

Assessing the suitability of the SLEUTH cellular automata model for capturing heterogeneous urban growth in developing cities: A case study in Northern Nigeria

Cellular automata (CA) models like SLEUTH (an acronym for slope, land use, excluded area, urban extent, transport-network and hill shade) have predominantly been developed and applied in developed countries. Modeling can serve as a tool to guide policy measures in facing urbanization challenges. However, developing cities have peculiar differences (heterogeneity, poor planning, and low infrastructure) thus the existing modeling approaches may not be able to apprehend heterogeneous urban growth. This research will use selected cities with similar spatial extents as controls but disparate urban extents, and growth indices to analyze the performance of SLEUTH simulations. Presumably, a comparison of the model simulations of the cities would display some significant differences, due to these variations and the scale of observation that has to be used for the model simulations. The results for the successfully calibrated cities (Kano/Funtua couple: 0.48/0.02. Katsina/Kaduna: 0.48/0.83 respectively) showed that in each city couple, the more expansive city with the most compact urban settlement pattern had a higher prediction accuracy, also predicted images of the cities showed underestimation of the urban areas over the years with the exception of Katsina city. The study further showed the model's effectiveness in modeling cities in developing countries, such as Nigeria. It is recommended that the type of urban growth experienced by cities be taken into consideration when implementing SLEUTH. Limitations of the study are centered on the inherent limitations of the model, the possibility of the occurrence of errors in data preparation, the scale and urban settlement type, which play an important role in the success of the calibration. Future research could be focused on adding other relevant inputs to the model and creating a metric that ascertains the best satellite image resolutions for a particular study area's growth coefficient values.

Population Dynamics of Indian Makerel (Rastrelliger kanagurta) in Northern Bone Bay Waters, Indonesia

This study aims to analyze the parameters of Rastralliger kanagurta population dynamics in the waters of Northern Bone Bay. To analyze the parameters of population dynamics, measurements were made of the total length of the sample fish in centimeters. The research was conducted in March – September 2022 at the Palopo City Pontap Fish Landing Site. Sampling is carried out every two weeks. The results of the growth parameter analysis obtained each value of growth coefficient = 0.84 per year, asymptotic length = 30.5 cm and to = -0.189 years. Furthermore, for mortality parameters, natural mortality was obtained at 1.64 per year, capture mortality = 2.47 per year, and total mortality at 4.11 peryear and exploitation rate at 0.6%. The results show that the growth rate of Rastralliger kanagurta is very high and can reach maximum length at a relative age of 15 years. Mortality parameters show that Rastralliger kanagurta mortality in northern Bone Bay waters is higher from fishing than natural mortality. The exploitation Rastralliger kanagurta in the waters of northern Bone Bay is 60% greater than the maximum exploitation rate of 50%. Based on the results of this study, management of fishery resources is needed so that the population is not disturbed.

Ichthyofauna of Merbau River, Leuser Ecosystem Area, Indonesia: species composition, diversity, biometric condition, potency, and conservation status

The Leuser Ecosystem Area (LEA) is one of the largest conservation areas in Southeast Asia. However, the explorations of ichthyofauna at LEA are still relatively scarce compared to other vertebrates fauna. We report the first ichthyofauna studies of the northern river of LEA in Aceh Province. This study aimed to determine the composition, diversity, biometric condition, potency, and conservation status of freshwater fish in Merbau River, LEA, Indonesia. Fish sampling was carried out at six research stations using selective gill nets, throwing net, hook, tray net, and scoop net. A total of 434 individual fish belonging to 21 species, nine families and six orders were collected from the sampling location. Cyprinidae was the predominant family obtained, namely 42.9%. Based on their conservation status, 85.7% of collected fish were categorized as Least Concern, 9.5% as Data Deficient, and 4.8% as Near Threatened. A total of 14 fish have the potential as consumption fish, two species have the potential as ornamental fish, and five others have the potential both as consumption and ornamental fish. All fish species collected had negative allometric growth patterns with growth coefficient values (b) ranging from 1.17–2.51. The diversity and evenness index of fish was categorized as moderate (H’ = 2.52) with stable conditions (E = 0.85).

Length-weight relationship and condition factor of endemic genus Seminemacheilus (Teloestei=Nemacheilidae) for Turkey

Abstract. This study was aimed to determine the length-weight relationships and Fulton s condition factors of the genus Seminemacheilus that is endemic for Turkey. The specimens were collected from 2017 to 2019 using an electrofishing device (SAMUS 1000MP). The total length and the total weight of the examined specimens ranged from 3.5 to 9.1 cm and from 0.31 to 7.52 g, respectively. Based on the results, the growth coefficient values b ranged from 2.56 (S. ispartensis) to 3.48 (S. attalicus). Also, the condition factor of the studied fishesranged from 0.77 (S. dursunavsari) to 1.11 (S. attalicus). This study represents the first reports of length-weight relationship data for S. ahmeti, S. attalicus, S. dursunav ari, S. ekmekciae, and S. ispartensis from Turkish inland waters and four new maximum total lengths for the Seminemacheilus species. The results of this study provide useful information for further fisheries management, fish population dynamic studies and comparisons in future studies.

Length-weight relationships native fish of Southern Altiplano: Lauca National Park, Chile

Dos géneros de peces, Orestias (Cyprinodontidae) y Trichomycterus (Trichomicteridae), habitan en el Parque Nacional Lauca, Reserva de la Biosfera de la UNESCO, ubicado en la sierra de los Andes en el norte de Chile. El presente estudio analizó la relación longitud-peso para cuatro especies nativas de Orestias (O. Parinacotensis, O. Laucaensis, O. Chungarensis y O. Piacotensis) y dos especies nativas de Tricomycterius (T. Chungaraensis y T. laucaensis), obtenido en siete localidades diferentes. Nuestros resultados mostraron que el crecimiento valores de los coeficientes “B” para Orestias varió de 2,89 (O. Parinacotensis) a través de 4,04 (O. P iacotensis) y Trichomycterus entre 2.53 (T. Laucaensis en Parinacota humedales) a través de 3,63 (T. laucaensis en Caquena río). Todas las relaciones talla-peso fueron significativas (p <0,01), con r 2 superior a 0,82. O. laucaensis, O. piacotensis y T. chungaraensis mostró un crecimiento alométrico positivo (b > 3). Sin embargo, dos especies O. parinacotensis y T. laucaensis mostró un crecimiento alométrico negativo (b <3). Sólo O. chungarensis mostró un crecimiento isométrico con b = 3. La intensa actividad antrópica, la introducción de peces exóticos y el cambio climático presentan riesgos importantes para una comunidad única de peces endémicos de los altos Andes. Two genera of fish, Orestias (Cyprinodontidae) and Trichomycterus (Trichomicteridae), inhabit in the Lauca National Park, UNESCO Biosphere Reserve, located at the Andes highlands in northern Chile. The present study analyzed the length-weight relationship for four native species of Orestias (O. parinacotensis, O. laucaensis, O. chungarensis and O. piacotensis) and two native species of Tricomycterius (T. chungaraensis and T. laucaensis), obtained at seven different localities. Our results showed that the growth coefficient values “b” for Orestias ranged from 2.89 (O. parinacotensis) through 4.04 (O. piacotensis) and Trichomycterus between 2.53 (T. laucaensis in Parinacota wetland) through 3.14 (T. laucaensis in Caquena River). All length-weight relationships were significant (p < 0.01), with r 2 higher than 0.82. O. laucaensis, O. piacotensis and T. chungaraensis showed positive allometric growth (b > 3). However, two species O. parinacotensis and T. laucaensis showed negative allometric growth (b < 3). Only O. chungarensis showed isometric growth with b = 3. Intense anthropic activity, exotic fish introduction, and climate change present important risks for a unique endemic fish community of the high Andes.

Biometric indices of five miniature fish from the catchment area of Kaptai Lake, Bangladesh

The present study reports on biometric indices comprising length-weight relationships (LWRs) of five miniature freshwater fish species from the Kaptai Lake, the largest lake in the People's Republic of Bangladesh. The study area included 3 stations in the 11,122 km2 catchment area of the lake and each station was sampled from November 2017 to April 2018 using push net (mesh size 2 mm) for capturing the species. The values of growth coefficient b of the LWRs (W = aTLb) of the species Oryzias dancena, Oryzias melastigma, Gobiopterus chuno, Brachygobius nunus and Badis chittagongis were 2.9575, 3.1467, 3.0535, 3.058 and 2.9396 with above 0.95 coefficient of correlation (r2). These results represent the first study of LWRs for these fish species which may help in management and conservation of the species in the whole country, including its geographical distribution.

Fish meal replacement with squilla (Oratosquilla nepa, Latreille) silage in a practical diet for the juvenile giant freshwater prawn, Macrobrachium rosenbergii de man, 1879

Replacement of fish meal with squilla silage in practical diet for the juvenile giant freshwater prawn, Macrobrachium rosenbergii, was evaluated. Five iso-nitrogenous and iso-caloric diets were prepared in which protein requirements were met with 100% fish meal (control, diet 1) and squilla silage replacing fish meal at 25, 50, 75 and 100% (diets 2, 3, 4 and 5, respectively). Water stability and water absorption of five feeds revealed significant differences (P < 0.05). The weight gain varied between a maximum of 248.50 ± 34.07% in diet 4 to lowest 132.45 ± 14.34% in diet 1. The average daily gain in weight in grams varied from 0.091 ± 0.01 (diet 5) to 0.154 ± 0.04 (diet 3), whilst the specific growth rate and gross growth coefficient values were recorded highest in diet 4. Highest survival rates (86.66 ± 5.77%) were recorded in both experimental diets 4 and 5. Low feed conversion ratio of 1.19 ± 0.21 was recorded from diet 4, whilst the highest value of 2.16 ± 0.09% was estimated from the diet 5. Proximate carcass composition showed highest crude protein content in post-larvae fed with diet 5 (47.24%) in contrast to lowest diet 1 (36.12%). Lipid values fluctuated significantly between 2.45 and 7.18% (P < 0.05) between treatments. The ash content significantly increased from diet 1 (16.34%) to diet 5 (20.69%) (P < 0.05). Highest feed efficiency (gain/feed) value was recorded in diet 4 (1.52 ± 0.22), whilst the diet 5 showed lowest value (0.99 ± 0.06). The results suggested that squilla silage can be utilised up to 75% of the protein in prawn diets for fish meal replacement.

Length-weight relationship and condition factor of Pethia ticto (Hamilton, 1822) from Gomti river in Sultanpur, Uttar Pradesh, India

This study describes the length-weight relation (LWR) of small indigenous fish Pethia ticto from Gomti River, Aamghat, Haliyapur, Sultanpur district 260 29N and 810 44E, 751m (msl) Uttar Pradesh, India. A total of 306 specimens were caught by random sampling method using traditional fishing gear as gillnet, cast net and dragnet of various mesh sizes from June 2016 to May 2017, once in a month. Total Length (mm) was measured from anteriormost part of the snout to the posterior-most part of the caudal fin and body weight (g) were taken by digital electronic balance. The analysis of data shows that the allometric coefficient is close to isometric value (3.0). Allometric growth indicates a more rotund population of fish when the values of growth coefficient are higher than 3.0 (b&gt;3). If the value of growth coefficient is less than 3.0, the population of fish is known to be less rotund. Isometric growth indicates that the shape of fish does not change as it grows (b=3). The coefficient of determination (R2 ) was also found significant (=0.97). Fulton’s condition factor further supports the results obtained ranged from 1.041 to 1.660 shows the degree of well being of a fish. This study is helpful in providing relevant information in the assessment of stock and estimation of the fish condition about its environment

Enhancing the dietary value of palm oil in the presence of lysolecithin in tiger shrimp, Penaeus monodon

The effect of four iso-nitrogenous and iso-lipidic diets containing soy lecithin and lysolecithin with fish oil (sardine) and palm oil on growth, digestibility, and fatty acid composition of tail muscle and non-muscle portions of tiger shrimp, Penaeus monodon, was evaluated. Shrimp fed with lysolecithin diets had significantly (P < 0.05) higher daily growth coefficient values (1.40–1.45% day−1) than those fed with soylecithin containing diets (1.32–1.37% day−1). Correspondingly, lysolecithin-supplemented diets showed significantly higher (P < 0.05) apparent digestibility coefficients (ADC) of fatty acids with both the oils due to higher emulsification ability of small micelle forming by lysolecithin. However, there were no significant differences in survival and FCR among all treatments. The fatty acid composition of the test diets reflected to a certain extent in the fatty acid composition of the muscle and non-muscle portions of shrimp. Arachidonic, eicosapentaenoic, and docosahexaenoic acid contents of muscle and non-muscle portions of shrimp were significantly (P < 0.05) higher in lysolecithin-supplemented diet compared to soylecithin-supplemented diet. The present results suggest that lysolecithin improved the fatty acid digestibility with its high emulsification properties that reflected in better performance by improving dietary value of palm oil.

Length-weight relationship and condition factor of seven fish species from Shahrbijar River, Southern Caspian Sea basin, Iran

Length-weight relationship and condition factor were estimated in seven fish species, including Barbus cyri, Capoeta gracilis, Alburnoides eichwaldii, Pseudorasbora parva, Ponticola cyrius, Cobitis keyvani and Acanthalburnus microlepis from Shahrbijar River, Guilan Province, Iran. A total of 416 specimens ranging from 18 to 135 mm in total length and from 0.06 to 19.25g in total weight were collected. Based on the results, growth coefficient values “b” ranged from 2.615 (in B. cyri) through 3.001 (in A. microlepis). All length-weight relationships were significant (p<0.05), with r2 higher than 0.819. The five species viz. C. gracilis, P. parva, C.keyvani, P. cyrius, and B. cyri showed allometric (b<3<b) while two species viz. A. microlepis and A. eichwaldii showed isometric (b=3) growth patterns. Condition factor ranged from 0.57 (in C.keyvani) through 1.11 (in P.cyrius). All linear regressions were highly significant (p<0.05). The present study provides the first baseline information on the length-weight relationships of the seven fish species from Shahrbijar River which may be useful for further fisheries management of these species.

Length-weight relationship and condition factor of seven fish species of Totkabon River (southern Caspian Sea basin), Guilan, Iran

Length-weight relationship and condition factor were investigated in seven fish species, including Barbus cyri , Capoeta gracilis , Alburnoides eichwaldi , Acanthalbarnus microlepis , Ponticola cyrius , Cobitis keyvani and Oxynemacheilus bergianus from Totkabon River. A total of 570 specimens ranging from 25.90 to 146.97 mm in total length and 0.1 to 260.3 g in total weight were collected. Based on the results, growth coefficient values “ b ” ranged from 2.429 ( A. microlpis ) to 3.71 ( C. keyvani ). All length-weight relationships were significant ( P <0.05), with r 2 greater than 0.856. The four species viz . A. microlepis , C. gracilis , P. cyrius and C. keyvani showed allometric ( b <3< b ) and three species viz . B. cyri , A. eichwaldi and O. bergianus isometric ( b = 3) growth patterns. Condition factor ranged from 0.544 ( O. bergianus ) to 0.940 ( P. cyrius ). All linear regressions were highly significant ( P <0.05). The result of this study may be useful for biologists and fishery managers.

Downstream Changes on a Tropical Fish Community Structure by Effluent from Wood Processing Factory

In order to plan a management programme for ensuring maximum production of fish in Cross River, impacted downstream changes in the fish community structure by effluents from wood processing industry, six years after establishment, was examined. Monthly samples were collected between January and December each year from 2000 to 2006 in three reaches (Upriver: I, Mid-river: II and Downriver: III) along the length of Cross River. Representatives of the fish families Osteoglossidae (i.e. Heterotis niloticus), Cichlidae (Tilapia melonopleura) and Characidae (Bryocinus nurse), Clupeidae (Cynothrissa sp), Mormyridae (Mormyrus deliciosus), Clariidae (Clarias gariepinus), Bagridae (Bagrus bayad) and Cyprinidae (Barbus occidentalis) were found to have declined in their importance compared to pre-industry period. On the other hand, Bagridae (Chrysichthys nigrodigitatus), Cichlidaae (Orechromis niloticus), Claridae (Clarias anguillaris) and Mochokidae (Synodontis clarias) have currently emerged as most important. Estimated value of growth coefficient (b) of the length-weight relationship changed from isometry (b approx. = 3) to negative allometry (b ≤ 3), condition factor values decreased from range between 0.53 and 1.30 to range between 0.22 and 0.62. Main feeding groups of fish; planktivores, carnivores and insectivores declined in numbers while omnivores and detritivores increased, resulting in dominance of benthic and semi-pelagic omnivores. Values of fecundity distribution varied from 56,012 ± 5234 eggs, mode 12,500 and median 58,345 to mean value 23,122 ± 232 eggs, mode 2500 and median 20,349, egg size from mean value; 1.82 ± 0.07 mm, mode 2.2, and median; 1.8 to values of 0.8 ± 0.04 mm, mode; 1.3 and median 1.1 and Gonadosomatic index from 20.5 ± 3.2, mode 19.1 ± 2.2 and median 21.4 to values of 12.4 ± 2.3, mode 4.5 and median 9.5 respectively. Three species found to have appeared in the river were Tilapia monody, Chrysichthys maurus and Synodontis violaceus. The appearance of these species and disappearance of 36 others indicates the restructuring of the fish community of the Cross River by effluents from the wood processing industry.

Evaluation of the Consistency of Low-Fat Mayonnaise by Squeezing Flow Viscometry

Lubricated squeezing flow viscometry was applied for the evaluation of the consistency of mayonnaise samples of 50% w/w oil content. Mayonnaise samples were prepared with the addition of four stabilizers: sodium alginate, xanthan gum, guar gum and carboxymethyl cellulose (CMC). Each stabilizer was added individually at concentrations from 0.5 to 2% w/w. In addition, a series of nine mayonnaise samples was prepared with mixtures of xanthan gum and guar gum in various ratios, at 1.5% w/w total concentration, aiming to determine synergistic effects between the two stabilizers. All samples were characterized as pseudoplastic since flow behavior index was shown to be lower than unity. Biaxial elongational viscosity, expressed as stress growth coefficient, was determined at specimen's compressive deformation 50%, because larger deformations lead to structural breakdown of highly viscous samples. Using the present method, the determination of stress growth coefficient was possible in the range from 40 to 300kPa·s. In all samples, stress growth coefficient was shown to increase with increasing concentrations of stabilizers. At concentrations ranging from 1.0 to 1.5%, CMC provided the most viscous emulsions, followed by those with xanthan gum and sodium alginate, while those with guar gum appeared as the least viscous. Conversely, at concentration of 0.75%, CMC was shown to be unable to form a sufficient network, thus providing a less viscous emulsion than the one by xanthan gum. All mixtures of xanthan gum and guar gum revealed synergistic action, where the highest stress growth coefficient values were observed in samples with xanthan gum/guar gum ratios of 30:70 and 40:60. The above mentioned values were higher by two or threefold (p<0.05) compared to those of samples of equal concentration (1.5%) prepared with the addition of xanthan gum or guar gum alone, respectively.

A study of the length – weight relationship and condition factor of &lt;i&gt;Pseudotolithus elongatus&lt;/i&gt; (Browdich, 1825) from Bonny Estuary Niger Delta, Nigeria

The length–weight relationship and condition factor of Pseudotolithus elongatus from Bonny estuary was studied for a period of twelve months. A total of one thousand seven hundred and twenty five (1725) fish specimens were used. The initial growth constant (a) was 0.0047 (combined), 0.0047 (males) and 0.048 (females). The length exponent values (b) were 3.1675 (combined), 3.1566 (males) and 3.1569 (females). The correlation growth coefficient values (r2) were 0.84 (combined), 0.81 (males) and 0.84 (females). Values for the mean condition factor ranged from 0.76±1.87 (June) to 0.88±.1.1145 (March). Pseudotolithus elongatus exhibited an allometric growth. There was a positive correlation between length and weight of both sexes. P. elongatus was also in a good condition. Keywords: Fish, length–weight relationship, condition factor, Bonny estuary, Nigeria

Effect of dietary energy content on gilthead sea bream (Sparus aurata) feeding behaviour and nutritional use of the diet

We have studied how the diet energy level affects gilthead sea bream (Sparus aurata) daily pattern of demand-feeding activity and nutritional use of the diet under summer- and winter-like conditions. To that end, animals were kept in a closed circuit under controlled temperature and photoperiod, and fed one of two commercial diets with either high (H: 238 g kg[superscript [-]1] fat) or low (L: 172 g kg[superscript [-]1] fat) energy content. In summer conditions (26 °C; 12 : 12 L : D), both diets yielded similar growth rate (0.7 ± 0.0 and 0.7 ± 0.1) and thermal unit growth coefficient values (0.6 ± 0.0 and 0.6 ± 0.0), and although the daily rate of delivered feed was somewhat higher for fish under the high-energy diet (16 ± 2 g kg[superscript [-]1] of fish) the difference was not significant. In winter conditions (17 °C; 9 : 15 L : D), on the other hand, no differences were found for any of the parameters evaluated. Thus, the higher lipid content of the diet does not appear to have any protein sparing effect. The 'summer' demand-feeding pattern displayed three daily peaks, which were quite apparent for fish under the low-energy diet, but rather smoothed for those that ate the energy-rich diet. This profile was replaced in winter conditions by a single peak around noon, and the animals also displayed a lower overall number of demands.

Recrutamento do peixe-rei, Atherinella brasiliensis (Quoy &amp; Gaimard) (Atheriniformes, Atherinopsidae), na margem continental da Baía de Sepetiba, Rio de Janeiro, Brasil

The silverside, Atherinella brasiliensis (Quoy & Gaimard, 1824), a resident species of the shallows of bays, estuaries and coastal lagoons, was studied during two annual cycles, using beach seines (July 1996 to June 1998), in the continental margin of the Sepetiba Bay, aiming to assess recruitment and distribution patterns. A wide recruitment period, with young-of-the-year appearing from early spring to early autumn, was shown, with peaks of juveniles (Total Length-LT = 10-30 mm) being recorded in two periods of the year; one in November and another in March. The highest abundances, of both juvenile and adults, were recorded in Coroa Grande and Itacuruca, sites located in the outer Bay, during the whole summer, with significant differences were found. In spite of not having been found any statistically significant relationship between the environmental factors and the occurrence of this species, a trend of higher abundance in colder and more saline waters was detected. High values of growth coefficient (K = 0.93) and low asymptotic lenght (L∞ = 11.6 cm) indicated that this species shows a high growth rate and short life cycle, with life span of 3.09 years, in this system.

Reproduction and growth of Jack-knife shrimp, Haliporoides sibogae, off south-western Kyushu, Japan

Jack-knife shrimp Haliporoides sibogae (Decapoda, Penaeoidea, Solenoceridae) is the target species in a boat seine fishery in the East China Sea off south-western Kyushu, Japan. The reproduction and growth of this species were studied based on a large number of specimens which were sampled during 19 months in a commercial fishing ground. The body length at sexual maturity for females was estimated to be 100 mm (2 year old). The spawning season continues from September to April and peaks during late January and late March. Only the 3 year old group of females matured in the early spawning season, while the 2 and 3 year old groups matured in the primary spawning season. The growth patterns for both sexes were well modelled by fitting the Pauly and Gaschüktz equations to the mean body lengths at various ages. The growth rates were highest between summer and autumn and lowest during the primary spawning season. Females grow faster and attain a greater size earlier than males of the same age group. The H. sibogae population off south-western Kyushu has lower values of asymptotic size and higher values of growth coefficient in comparison to other local populations of this species, such as those in Kii Channel and eastern Australia.

Kinetics of growth and accumulation of aflatoxin B1 by Aspergillus parasiticus in the presence of butylated hydroxyanisole, isoprothiolane, and nystatin

Growth of Aspergillus parasiticus and accumulation of aflatoxin B(1) in the medium that contained antifungal agents were monitored during the growth cycle of the mold. The antifungal agents tested are the food additive (antioxidant), butylated hydroxyanisole (BHA), the pesticide, isoprothiolane, and the antibiotic, nystatin. Growth of the mold was quantified using a newly developed criterion, named the growth coefficient (GC). The GC values were calculated from the growth parameters of the logistic function that fits the growth curve of the mold. At the range of concentrations of additives studied, maxima of growth inhibition were 31.3, 23.1, and 43.6% at 60 ppm of BHA, 70 ppm of isoprothiolane, and 45 units of nystatin/mL, respectively. The ability of the mold to accumulate aflatoxin B(1) in its medium [as measured by the accumulation rate constant (alpha)] In the presence of various levels of the antifungal agents was concentration-dependent. Sixty parts per million of BHA decreased the value of alpha by 71.7%, 30 units of nystatin/mL was the most effective concentration of that antibiotic and resulted in only 23.5% inhibition, and isoprothiolane at all its levels stimulated elaboration of aflatoxin B(1) by the mold.