Ivan Bezerra Allaman

Interrelationships between morphometric variables and rounded fish body yields evaluated by path analysis

The objective of this study was to verify which morphometric measures and ratios are more directly associated with the weight and body yields of rounded fish. A total of 225 specimens of rounded fish (59 pacus, 61 tambaquis, 52 tambacus and 53 paquis) with average weight of 972.43 g (±115.52 g) were sampled, stunned, slaughtered, weighed, measured, and processed for morphometric and processing yield analysis. The morphometric measures taken were: standard length (CP); head length (CC); head height (AC); body height (A1); and body width (L1). For completeness, the following morphometric ratios were calculated: CC/CP, AC/CP, A1/CP, L1/CP, CC/A1, AC/A1, L1/A1, CC/AC and L1/CC. The yields of carcass, filet, rib and filet with rib were estimated after processing. Initially, a stepwise procedure was performed in order to eliminate multicollinearity problems among the morphometric variables, and the phenotypic correlations were then calculated for the dependent variables (weight and body yields) and independent variables (morphometric measurements and ratios). These correlations were later deployed in direct and indirect effects through path analysis, and the direct and indirect contributions of each variable were measured in percentage terms. The CC and A1 measures were important for determining the weight of rounded fish. The CC/A1 ratio was the variable most directly associated with carcass yield. For filet, filet with rib and rib yields, the L1/CC ratio was found to be more appropriate and can be used directly.

Equações de predição para estimar valores da energia metabolizável de alimentos concentrados energéticos para aves utilizando meta-análise

Prediction equations were obtained for the apparent metabolizable energy (EMAn) values of energetic feedstuffs used in broiler chicken diets by meta-analysis. A bibliographical review of the studies carried out in Brazil was performed to collect information concerning energy values and chemical composition (CP, EE, MM, CF, NDF, and ADF) of feedstuffs. The effects of gender (male, female and mixed), age (1st and 2nd week, 3rd and 4th week, 5th and 6th week, and older 6th weeks or indefinite), and the metabolism assay methodology (excrete total collection or forced fed + excrete total collection) were also considered, constituting a factorial scheme (3x4x2). The stepwise procedure was used to study the association among equation variables by their importance, and Proc Reg (SAS) was used to fit the multiple linear regression model. The equations which best estimated the EAMn of the energetic feedstuffs were AME = 4,371.18 - 26.48CP + 30.65EE - 126.93MM - 52.26CF - 25.14NDF + 24.40FDA (R2=0.81) and AME = 4,205.23 + 30.58EE - 130.35MM - 58.29CF - 28.31NDF + 16.71NDA (R2=0.81). NDF and ADF variables were important in the equations, influencing the feedstuffs energetic values.

Métodos alternativos de restrição alimentar na muda forçada de poedeiras comerciais

Alternative methods were assessed of qualitative feed restriction compared to the conventional forced molt technique. Four hundred and eighty Babcock hens were used distributed in three levels of feed restriction (100, 75 and 50%) and three body weight reduction percentages (15, 20 and 25%), with five replications of 32 hens. When the birds reached the body weight reduction percentage the packed cell volume, percentages of ovary, oviduct, gizzard, intestine, abdominal fat and oviduct length were determined. Starting on day 28 and during five 28-day periods the quantitative and qualitative characteristics of production after forced molt were measured. The largest restriction period occurred at 50% of restriction that resulted in the smallest percentages of abdominal fat (0.66%), ovary (0.60%), oviduct (0.77%) and oviduct length (32 cm). The egg production percentage was higher in the first period, for the 75 and 100% restriction methods with up to 15 and 20% body weight reduction, respectively. However, for the birds with 50% restriction and 25% body weight reduction, the highest productions (86.80 and 83.20%) occurred in the 4th and 5th periods. Qualitative feed restriction at 50% of the diet with feed and rice hulls, because it was less aggressive, resulted in better welfare conditions and facilitated farm management.

Equações de predição para estimar os valores da EMAn de alimentos proteicos para aves utilizando a meta-análise

Este trabalho foi realizado para se obter uma equacao de predicao para estimar os valores de energia metabolizavel aparente corrigida (EMAn) dos alimentos proteicos usualmente utilizados em racoes para frangos de corte utilizando-se o principio da meta-analise. Realizou-se uma revisao bibliografica de estudos no Brasil para catalogar informacoes sobre valores de EMAn e composicao quimica dos alimentos: proteina bruta (PB), extrato etereo (EE), materia mineral (MM), fibra bruta (FB), fibra em detergente neutro (FDN) e fibra em detergente acido (FDA). Foram considerados os efeitos de: sexo, em tres niveis (macho, femea e mistos); idade, em quatro niveis (1a e 2a semana de vida, 3a e 4a semana, 5a e 6a semana e acima ou indefinido) e metodologia empregada no metabolismo em dois niveis: coleta total (CT) e alimentacao forcada + (CT). Os dados foram analisados em um esquema fatorial 3 × 4 × 2, podendo totalizar ate 24 grupos, adotando-se o procedimento Stepwise para a selecao de variaveis e o Proc Reg do (SAS) para ajustar o modelo de regressao linear multipla. A equacao obtida que melhor se ajustou foi EMAn = 2707,71 + 58,63EE - 16,06FDN (R2 = 0,81), sendo o EE a variavel mais importante, em se tratando de possiveis variacoes nos teores energeticos dos alimentos proteicos.

Weight and morphometric growth of different strains of tilapia (Oreochromis sp)

The objective of this study was to evaluate the morphometric growth and weight gain of strains of tilapia (Thai, Red, UFLA and Commercial) by nonlinear models. Initially, 500 male fingerlings of each strain, at 85 (Red and UFLA) and 86 (Thai and Commercial) days of age, were stocked separately in raceways with 56 m3. Twenty fish of each strain were randomly sampled, weighed and measured monthly. Five nonlinear models (Brody, von Bertalanffy, Gompertz, logistic and exponential) were tested, choosing one that best fit to the data. The variables studied were: weight, standard length (SL), head length (HL), height 1 (H1), height 2 (H2), height 3 (H3), first distance (D1), second distance (D2), first width (W1), second width (W2) and third width (W3). The exponential model had the best fit to weight and morphometric data, with the exception of W2, in which the best fitted model was von Bertalanffy. The convergence of the exponential model to data indicates that the cultivation period studied was not enough for the strains to reach maturity weight. The UFLA strain presented the lowest value for parameter a (initial weight estimate), 8.71 g, and the highest for parameter k (specific growth rate), 0.0127, when compared with other evaluated strains. However, the highest k of UFLA was not enough to overcome the final weight observed for the Commercial strain (603.1 g), which was higher than all other strains. Regarding the morphometric measurements, the UFLA strain also had the highest k for the variables SL, HL, HH, H1, H2, H3 and D2, and similar k to Commercial and Thai strains for the variables D1 and W3 respectively. The strains differ as to weight gain and morphometric growth.

Performance and carcass traits in the diallel crossing of pacu and tambaqui

With the purpose of evaluating the changes and the degree of heterosis on performance and carcass traits of fish from the diallel crossing between Pacu and Tambaqui, four genetic groups were generated through hormonal induction: pacu, tambaqui, tambacu and paqui. For 196 days, 400 juveniles of each genetic group were stocked in a pond divided into four parts of equal size, one for each group. At the end of this period, when the fish weighed on average 1024 g (±115.52 g), 20 specimens of each genetic group were sampled, weighed, measured: head length; standard length; body height; and width; and also processed resulting in following body yield: viscera; carcass; head; fillet; rib; residue and skin yields. There was positive heterosis for body weight, viscera and skin yield and head measures and negative heterosis for carcass and filet yield and body width, indicating that the hybrids have better performance on weight gain, but are inferior in relation to the carcass conformation.

Efeito materno e paterno sobre as taxas de fertilização e eclosão em curimba (Prochilodus lineatus)

Avaliou-se o quanto femeas e machos contribuem para a variacao total das taxas de fertilizacao e de eclosao em curimba (Prochilodus lineatus). Utilizou-se semen criopreservado proveniente de cinco machos para fertilizar ovocitos de seis femeas em um esquema fatorial cruzado 5x6, totalizando 30 familias. Alem das caracteristicas reprodutivas dos machos e femeas, foram avaliadas as taxas de fertilizacao e eclosao para computo dos efeitos materno e paterno. Os componentes da variância foram estimados por meio da maxima verossimilhanca restrita, sendo construidos intervalos Highest Posterior Density (HPD) para cada componente. Verificou-se que as femeas contribuiram muito mais para a variacao total em relacao aos machos para as taxas de fertilizacao e eclosao. Para a taxa de fertilizacao, as femeas contribuiram com 26,3% da variacao total e os machos com 8,9%. Em relacao a taxa de eclosao, as femeas contribuiram com 11,9% e os machos com 1,6%. Concluiu-se que houve efeito materno sobre as taxas de fertilizacao e eclosao e que o efeito paterno avaliado individualmente foi pouco expressivo ou ate mesmo insignificante.

Deposition of bodily chemical components in the carcass of tilapia (oreochromis sp.) strains

The knowledge of how animals deposited chemical components as water, protein, fat and ash in the carcass is importance for the formulation of a balanced diet, allowing maximum performance with a low environmental impact. So, the study was carried out to evaluate the influence of different tilapia strains (Chitralada, Commercial, Red and Universidade Federal de Lavras [UFLA]) on the deposition of bodily chemical components in the carcass. The bodily components analyzed were water, protein, fat and ash. For the determination of the bodily chemical deposition curves by age, the exponential, Brody, logistic, Gompertz and von Bertalanffy models were adjusted. The Commercial and UFLA strains deposited water at a faster speed (P 0.05) for the logistic model parameter between Red, UFLA and Commercial strains for fat, which presented a maximum fat deposition (0.23 g) at 310 days of age. Regarding ash deposition, the Commercial strain presented a higher maximum deposition (0.10 g) at 337 days, occurring later than the other strains that presented maximum deposition (0.033g) at 254 days of age. Thus, it was concluded that the genetic strains evaluated differ in chemical deposition curves of water, protein, fat and ash.