Survey
A community-based cross-sectional survey was conducted in Ebinat district from May to July, 2016. It is one of the 12 districts of South Gondar administrative zone of Amhara region with an estimated area of 2494.27 km
2 having 35 rural and 2 urban Kebeles administrations. The sample size for the survey was determined using a single population proportion formula considering the following assumptions: Proportion of appropriate complementary feeding (
p = 10.75%) in Tigray region, Northern Ethiopia [
17]; 95% level of confidence (Z = 1.96); marginal error (d = 5%)
$$ n=\frac{\mathrm{Z}\ \upalpha /2\Big)\ 2\mathrm{p}\ \left(1-\mathrm{p}\right)}{\mathrm{d}2\ } $$
From above formula, the calculated sample size was 147. By considering design effect of 2 and non-response rate of 10%, the final sample size was estimated to be 324.
The district was purposively selected due to its high level of vulnerability to food insecurity and has a very long history of aid [
12]. In the district there are 37 kebeles of which 20% were randomly selected. Proportional to size allocation method was used to take appropriate sample from each kebele. Finally, systematic random sampling method was used to select respondent households. When more than one, mother-infant/child pairs were randomly selected.
Data for the survey were collected using a validated questionnaire adapted from the Ethiopian Health and Demographic Survey and WHO and LINKAGE project which were designed to assess infant and young child feeding practices in developing countries [
4,
18,
19]. A structured questionnaire was used to collect data on maternal complementary feeding practices using four indicators; timely introduction of complementary feeding, minimum dietary diversity, minimum meal frequency and minimum acceptable diet. The indicators were operationalized as follows [
20].
Timely introduction of complementary feeding: proportion of children at the age of 6–23 months who started complementary foods at 6th month.
Minimum dietary diversity: proportion of children at the age of 6–23 months who consumed foods from four or more food groups during the previous day. The seven food groups used for formulation of this indicator were: grains, roots and tubers; legumes and nuts; dairy products (milk, yogurt, cheese); flesh foods (meat, chicken and liver/organ meats); eggs; vitamin A rich fruits and vegetables; and other fruits and vegetables.
Minimum meal frequency: proportion of breastfed and non-breastfed children at the age of 6–23 months who got solid, semi-solid or soft foods the minimum number of times or more (2 times for breastfed infants 6–8 months; 3 times for breastfed children 9–23 months and 4 times for non-breastfed children 6–23 months) in the preceding day of the survey.
Minimum acceptable diet: proportion of breastfed children at the age of 6–23 months who had at least the minimum dietary diversity and the minimum meal frequency during the preceding day of the survey.
Appropriate complementary feeding practice: If the mother responds correctly all the above four indicators and if at least one indicator was not fulfilled, it was assumed to be inappropriate.
The data quality for the survey was ensured through training of data collectors, supervision and pre-test on 10% of the sample size. The questionnaire was prepared in English, translated in to Amharic and contextualized to the local situation. Pre-test was done before actual data collection. The completeness and consistency of the collected data have been checked before the study participants leave. The survey data were entered in to Epi Info version 6, checked for missing values and outliers and analyzed using SPSS (SPSS version 20).
Laboratory analysis
Most commonly used cereals for complementary feeding were Teff (Kuncho) and wheat (LOGAWSHIBO; TT14) and collected from Amhara seed enterprise. In all the treatments (sample preparation, laboratory determination and data analysis), the cereals were processed separately.
Sample materials were cleaned manually to remove husks, damaged grains, stones, dust, light materials, glumes, stalks, undersized and immature grains and other extraneous materials.
The cleaned grains of each cereal were dried in drying oven at 55 ͦC for about 2 h to facilitate and make the milling process conducive. The dried cereals were milled into flour to pass through a 1 mm aperture size test sieve to obtain a fine powder. The milled samples were then packed in airtight polythene plastic bags until further analysis.
Suspensions of cereals flour in de-ionized water were prepared in plastic containers at a concentration of 1:3 dilutions (w/v). The cereals flour slurries were allowed to ferment spontaneously at room temperature (20–23 ͦC) for 0, 12, 24, 36, 48 and 72 h in 12 plastic containers. The supernatant was decanted and samples were withdrawn. The fermented samples were transferred to aluminum dishes after each fermentation time and dried in a hot air oven-drier at 70 °C for 36 h. All samples were analyzed for Phytate, tannin and minerals (Ca, Fe, and Zn).
Phytate was determined by the method of Latta and Eskin [
21] which was later modified by Vantraub and Lapteva [
22]. About 0.1000 g of fresh samples were extracted with 10 ml 2.4% HCl in a mechanical shaker for 1 h at an ambient temperature and centrifuged at 3000 rpm for 30 min. The clear supernatant was used for phytate estimation. A 2 ml of Wade reagent (containing 0.03% solution of FeCl
3.6H
2O and 0.3% of sulfosalicilic acid in water) was added to 3 ml of each sample solution and the mixture was mixed on a Vortex for 5 s. The absorbances of the sample solutions were measured at 500 nm using UV-VIS spectrophotometer. A series of standard solutions of phytic acid were prepared in 0.2 N HCl. A 3 ml of standard was added into 15 ml of centrifuge tubes with 3 ml of water which was used as a blank. A 1 ml of the Wade reagent was added to each test tube and the solution was mixed on a Vortex mixer for 5 s. Then mixtures were centrifuged for 10 min and the absorbances’ of the solutions (both the sample and standard) were measured at 500 nm by using de-ionized water as a blank. Standard curves were made from absorbance versus concentration and the slope and intercept was used for calculation. Phytate: mineral molar ratios were calculated using the molecular weight of IP6 = 660.
Tannin content was determined by the method of Burns [
23] latter modified by Maxson and Rooney [
24]. About 2.0 g of the samples were weighed in a screw cap test tube. The samples were extracted with 10 ml of 1% HCl in methanol for 24 h at room temperature with mechanical shaking and the solutions were centrifuged at 1000 rpm for 5 min after 24 h shaking. A 1 ml of supernatant was taken and mixed with 5 ml of vanillin-HCl reagent (prepared by mixing equal volume of 8% HCl in methanol and 4% vanillin in methanol). D-catechin was used as standard for condensed tannin determination. A 40 mg of D-catechin was weighed and dissolved in 1000 ml of 1% HCl in methanol and used as stock solution. A 0, 0.2, 0.4, 0.6, 0.8 and 1 ml of stock solutions were taken in test tube and the volume of each test tube was accustomed to 1 ml with 1% HCl in methanol. A 5 ml of vanillin-HCl reagent was added into each test tube. After 20 min, the absorbance of sample solutions and the standard solutions were measured at 500 nm by using water to zero the spectrophotometer. The calibration curves were made from the series of standard solutions using SPSS-20. Standard curves were prepared from absorbance versus concentration and the slopes and intercepts were used for calculation.
The mineral contents (calcium, iron, and zinc) were determined by the procedure of AOAC (1984) using an Atomic Absorption Spectrophotometer. After removal of organic material by dry ashing, the residue was dissolved in dilute acid. The solution was sprayed into the flame of Atomic Absorption Spectrophotometer and the absorption of the metal to be analyzed was measured at a specific wavelength. The stock standard solutions of minerals (iron, zinc and calcium) were diluted with 0.3 N HCl to concentrations that fall within the working range (0, 0.6, 1.0, 1.4, 1.8, μg/ml for zinc analysis; 1.0, 1.5, 2.5, and 3.0 μg/ml for calcium analysis and 0, 2.0, 6.0, 10.0 12.0 μg/ml for iron analysis). The ash obtained from dry ashing was mixed with 5 ml of 6 N HCl and dried on a low temperature hot plate. A 7 ml of 3 N HCl was added to the dried ash and heated on the hot plate until the solution just boils. The ash solution was cooled to room temperature at open air in a hood and filtered through a filter paper into a 50 ml graduated flask. A 5 ml of 3 N HCl was added into each crucible dishes and heated until the solution just boiled, cooled, and filtered into the flask. The crucible dishes were again washed three times with de-ionized water and the washings were filtered into the flask. A 2.5 mL of 10% Lanthanum chloride solution was added into each graduated flask. Then the solution was cooled and diluted to the mark (50 ml) with de-ionized water. A blank was prepared by taking the same procedure as the sample.
For all experiments, determinations were made in triplicates. Errors were calculated as standard deviations of the mean (SD) and SAS 9.1.3 service pack 4 was used to analyze the results. Means were separated using Duncan’s Multiple Range Test. Significance was accepted at 0.05 level of probability.